diff --git a/gerbmerge/amacro.py b/gerbmerge/amacro.py
index f6b0e21..4d47720 100644
--- a/gerbmerge/amacro.py
+++ b/gerbmerge/amacro.py
@@ -112,7 +112,7 @@ class ApertureMacroPrimitive:
       valids = None
 
     if valids is None:
-      raise RuntimeError, 'Undefined aperture macro primitive code %d' % code
+      raise RuntimeError('Undefined aperture macro primitive code %d' % code)
 
     # We expect exactly the number of fields required, except for macro
     # type 4 which is an outline and has a variable number of points.
@@ -126,18 +126,18 @@ class ApertureMacroPrimitive:
     #   - last field is rotation
     if self.code==4:
       if len(fields) < 2:
-        raise RuntimeError, 'Outline macro primitive has way too few fields'
+        raise RuntimeError('Outline macro primitive has way too few fields')
 
       try:
         N = int(fields[1])
       except:
-        raise RuntimeError, 'Outline macro primitive has non-integer number of points'
+        raise RuntimeError('Outline macro primitive has non-integer number of points')
 
       if len(fields) != (5+2*N):
-        raise RuntimeError, 'Outline macro primitive has %d fields...expecting %d fields' % (len(fields), 3+2*N)
+        raise RuntimeError('Outline macro primitive has %d fields...expecting %d fields' % (len(fields), 3+2*N))
     else:
       if len(fields) != len(valids):
-        raise RuntimeError, 'Macro primitive has %d fields...expecting %d fields' % (len(fields), len(valids))
+        raise RuntimeError('Macro primitive has %d fields...expecting %d fields' % (len(fields), len(valids)))
 
     # Convert each parameter on the input line to an entry in the self.parms
     # list, using either int() or float() conversion.
@@ -150,7 +150,7 @@ class ApertureMacroPrimitive:
       try:
         self.parms.append(converter(fields[parmix]))
       except:
-        raise RuntimeError, 'Aperture macro primitive parameter %d has incorrect type' % (parmix+1)
+        raise RuntimeError('Aperture macro primitive parameter %d has incorrect type' % (parmix+1))
 
   def setFromLine(self, line):      
     # Account for DOS line endings and get rid of line ending and '*' at the end
@@ -164,12 +164,12 @@ class ApertureMacroPrimitive:
       try:
         code = int(fields[0])
       except:
-        raise RuntimeError, 'Illegal aperture macro primitive code "%s"' % fields[0]
+        raise RuntimeError('Illegal aperture macro primitive code "%s"' % fields[0])
       self.setFromFields(code, fields[1:])
     except:
-      print '='*20
-      print "==> ", line
-      print '='*20
+      print('='*20)
+      print("==> ", line)
+      print('='*20)
       raise
 
   def rotate(self, flip):
@@ -283,7 +283,7 @@ def parseApertureMacro(s, fid):
 
       M.add(P)
     else:
-      raise RuntimeError, "Premature end-of-file while parsing aperture macro"
+      raise RuntimeError("Premature end-of-file while parsing aperture macro")
   else:
     return None
 
@@ -295,7 +295,7 @@ def addToApertureMacroTable(AM):
 
   # Must sort keys by integer value, not string since 99 comes before 100
   # as an integer but not a string.
-  keys = map(int, map(lambda K: K[1:], GAMT.keys()))
+  keys = list(map(int, [K[1:] for K in list(GAMT.keys())]))
   keys.sort()
 
   if len(keys):
@@ -338,25 +338,23 @@ if __name__=="__main__":
   MR = M.rotated(0)
 
   # Generate the Gerber so we can view it
-  fid = file('amacro.ger', 'wt')
-  print >> fid, \
-"""G75*
+  fid = open('amacro.ger', 'wt')
+  print("""G75*
 G70*
 %OFA0B0*%
 %FSLAX24Y24*%
 %IPPOS*%
-%LPD*%"""
+%LPD*%""", file=fid)
   M.writeDef(fid)
   MR.writeDef(fid)
-  print >> fid, \
-"""%ADD10TEST*%
+  print("""%ADD10TEST*%
 %ADD11TESTR*%
 D10*
 X010000Y010000D03*
 D11*
 X015000Y010000D03*
-M02*"""
+M02*""", file=fid)
   fid.close()
 
-  print M
-  print MR
+  print(M)
+  print(MR)
diff --git a/gerbmerge/aptable.py b/gerbmerge/aptable.py
index 51eb253..51641bc 100644
--- a/gerbmerge/aptable.py
+++ b/gerbmerge/aptable.py
@@ -168,17 +168,17 @@ def parseAperture(s, knownMacroNames):
         code, dimx, dimy = match.groups()
 
       if ap[0] in ('Macro',):
-        if knownMacroNames.has_key(dimx):
+        if dimx in knownMacroNames:
           dimx = knownMacroNames[dimx]    # dimx is now GLOBAL, permanent macro name (e.g., 'M2')
         else:
-          raise RuntimeError, 'Aperture Macro name "%s" not defined' % dimx
+          raise RuntimeError('Aperture Macro name "%s" not defined' % dimx)
       else:
         try:
           dimx = float(dimx)
           if dimy:
             dimy = float(dimy)
         except:
-          raise RuntimeError, "Illegal floating point aperture size"
+          raise RuntimeError("Illegal floating point aperture size")
 
       return Aperture(ap, code, dimx, dimy)
 
@@ -221,7 +221,7 @@ def constructApertureTable(fileList):
     # [andreika]: units conversion
     units_div = 1.0
 
-    fid = file(fname,'rt')
+    fid = open(fname,'rt')
     for line in fid:
       # Get rid of CR
       line = line.replace('\x0D', '')
@@ -276,19 +276,19 @@ def constructApertureTable(fileList):
 
   # Now, go through and assign sequential codes to all apertures
   code = 10
-  for val in AT.values():
+  for val in list(AT.values()):
     key = 'D%d' % code
     GAT[key] = val
     val.code = key
     code += 1
 
   if 0:
-    keylist = config.GAT.keys()
+    keylist = list(config.GAT.keys())
     keylist.sort()
-    print 'Apertures'
-    print '========='
+    print('Apertures')
+    print('=========')
     for key in keylist:
-      print '%s' % config.GAT[key]
+      print('%s' % config.GAT[key])
     sys.exit(0)
 
 def findHighestApertureCode(keys):
@@ -304,7 +304,7 @@ def findHighestApertureCode(keys):
 def addToApertureTable(AP):
   GAT = config.GAT
 
-  lastCode = findHighestApertureCode(GAT.keys())
+  lastCode = findHighestApertureCode(list(GAT.keys()))
   code = 'D%d' % (lastCode+1)
   GAT[code] = AP
   AP.code = code
@@ -315,7 +315,7 @@ def findInApertureTable(AP):
   """Return 'D10', for example in response to query for an object
      of type Aperture()"""
   hash = AP.hash()
-  for key, val in config.GAT.items():
+  for key, val in list(config.GAT.items()):
     if hash==val.hash():
       return key
 
@@ -335,16 +335,16 @@ def findOrAddAperture(AP):
 if __name__=="__main__":
   constructApertureTable(sys.argv[1:])
 
-  keylist = config.GAMT.keys()
+  keylist = list(config.GAMT.keys())
   keylist.sort()
-  print 'Aperture Macros'
-  print '==============='
+  print('Aperture Macros')
+  print('===============')
   for key in keylist:
-    print '%s' % config.GAMT[key]
+    print('%s' % config.GAMT[key])
 
-  keylist = config.GAT.keys()
+  keylist = list(config.GAT.keys())
   keylist.sort()
-  print 'Apertures'
-  print '========='
+  print('Apertures')
+  print('=========')
   for key in keylist:
-    print '%s' % config.GAT[key]
+    print('%s' % config.GAT[key])
diff --git a/gerbmerge/config.py b/gerbmerge/config.py
index 721e9ee..28a629c 100644
--- a/gerbmerge/config.py
+++ b/gerbmerge/config.py
@@ -15,7 +15,7 @@ http://github.com/unwireddevices/gerbmerge
 """
 
 import sys
-import ConfigParser
+import configparser
 import re
 import string
 
@@ -116,7 +116,7 @@ MinimumFeatureDimension = {}
 # hash string. The value is the aperture code (e.g., 'D10') or macro name (e.g., 'M5').
 def buildRevDict(D):
   RevD = {}
-  for key,val in D.items():
+  for key,val in list(D.items()):
     RevD[val.hash()] = key
   return RevD
 
@@ -127,12 +127,12 @@ def parseStringList(L):
   if 0:
     if L[0]=="'":
       if L[-1] != "'":
-        raise RuntimeError, "Illegal configuration string '%s'" % L
+        raise RuntimeError("Illegal configuration string '%s'" % L)
       L = L[1:-1]
 
     elif L[0]=='"':
       if L[-1] != '"':
-        raise RuntimeError, "Illegal configuration string '%s'" % L
+        raise RuntimeError("Illegal configuration string '%s'" % L)
       L = L[1:-1]
 
   # This pattern matches quotes at the beginning and end...quotes must match
@@ -153,14 +153,14 @@ def parseToolList(fname):
   TL = {}
 
   try:
-    fid = file(fname, 'rt')
-  except Exception, detail:
-    raise RuntimeError, "Unable to open tool list file '%s':\n  %s" % (fname, str(detail))
+    fid = open(fname, 'rt')
+  except Exception as detail:
+    raise RuntimeError("Unable to open tool list file '%s':\n  %s" % (fname, str(detail)))
 
   pat_in  = re.compile(r'\s*(T\d+)\s+([0-9.]+)\s*in\s*')
   pat_mm  = re.compile(r'\s*(T\d+)\s+([0-9.]+)\s*mm\s*')
   pat_mil = re.compile(r'\s*(T\d+)\s+([0-9.]+)\s*(?:mil)?')
-  for line in fid.xreadlines():
+  for line in fid:
     line = string.strip(line)
     if (not line) or (line[0] in ('#', ';')): continue
 
@@ -182,7 +182,7 @@ def parseToolList(fname):
     try:
       size = float(size)
     except:
-      raise RuntimeError, "Tool size in file '%s' is not a valid floating-point number:\n  %s" % (fname,line)
+      raise RuntimeError("Tool size in file '%s' is not a valid floating-point number:\n  %s" % (fname,line))
 
     if mil:
       size = size*0.001  # Convert mil to inches
@@ -192,8 +192,8 @@ def parseToolList(fname):
     # Canonicalize tool so that T1 becomes T01
     tool = 'T%02d' % int(tool[1:])
 
-    if TL.has_key(tool):
-      raise RuntimeError, "Tool '%s' defined more than once in tool list file '%s'" % (tool,fname)
+    if tool in TL:
+      raise RuntimeError("Tool '%s' defined more than once in tool list file '%s'" % (tool,fname))
 
     TL[tool]=size
   fid.close()
@@ -215,38 +215,38 @@ def parseToolList(fname):
 def parseConfigFile(fname, Config=Config, Jobs=Jobs):
   global DefaultToolList
 
-  CP = ConfigParser.ConfigParser()
-  CP.readfp(file(fname.rstrip(),'rt'))
+  CP = configparser.ConfigParser()
+  CP.readfp(open(fname.rstrip(),'rt'))
 
   # First parse global options
   if CP.has_section('Options'):
     for opt in CP.options('Options'):
       # Is it one we expect
-      if Config.has_key(opt):
+      if opt in Config:
         # Yup...override it
         Config[opt] = CP.get('Options', opt)
 
-      elif CP.defaults().has_key(opt):
+      elif opt in CP.defaults():
         pass   # Ignore DEFAULTS section keys
 
       elif opt in ('fabricationdrawing', 'outlinelayer'):
-        print '*'*73
-        print '\nThe FabricationDrawing and OutlineLayer configuration options have been'
-        print 'renamed as of GerbMerge version 1.0. Please consult the documentation for'
-        print 'a description of the new options, then modify your configuration file.\n'
-        print '*'*73
+        print('*'*73)
+        print('\nThe FabricationDrawing and OutlineLayer configuration options have been')
+        print('renamed as of GerbMerge version 1.0. Please consult the documentation for')
+        print('a description of the new options, then modify your configuration file.\n')
+        print('*'*73)
         sys.exit(1)
       else:
-        raise RuntimeError, "Unknown option '%s' in [Options] section of configuration file" % opt
+        raise RuntimeError("Unknown option '%s' in [Options] section of configuration file" % opt)
   else:
-    raise RuntimeError, "Missing [Options] section in configuration file"
+    raise RuntimeError("Missing [Options] section in configuration file")
 
   # Ensure we got a tool list
-  if not Config.has_key('toollist'):
-    raise RuntimeError, "INTERNAL ERROR: Missing tool list assignment in [Options] section"
+  if 'toollist' not in Config:
+    raise RuntimeError("INTERNAL ERROR: Missing tool list assignment in [Options] section")
 
   # Make integers integers, floats floats
-  for key,val in Config.items():
+  for key,val in list(Config.items()):
     try:
       val = int(val)
       Config[key]=val
@@ -283,7 +283,7 @@ def parseConfigFile(fname, Config=Config, Jobs=Jobs):
       for index in range(0, len(temp), 2):
         MinimumFeatureDimension[ temp[index] ] = float( temp[index + 1] )
     except:
-      raise RuntimeError, "Illegal configuration string:" + Config['minimumfeaturesize']
+      raise RuntimeError("Illegal configuration string:" + Config['minimumfeaturesize'])
 
   # Process MergeOutputFiles section to set output file names
   if CP.has_section('MergeOutputFiles'):
@@ -303,10 +303,10 @@ def parseConfigFile(fname, Config=Config, Jobs=Jobs):
 
     # Ensure all jobs have a board outline
     if not CP.has_option(jobname, 'boardoutline'):
-      raise RuntimeError, "Job '%s' does not have a board outline specified" % jobname
+      raise RuntimeError("Job '%s' does not have a board outline specified" % jobname)
     
     if not CP.has_option(jobname, 'drills'):
-      raise RuntimeError, "Job '%s' does not have a drills layer specified" % jobname
+      raise RuntimeError("Job '%s' does not have a drills layer specified" % jobname)
 
     for layername in CP.options(jobname):
       if layername[0]=='*' or layername=='boardoutline':
@@ -323,10 +323,10 @@ def parseConfigFile(fname, Config=Config, Jobs=Jobs):
   del apfiles
 
   if 0:
-    keylist = GAMT.keys()
+    keylist = list(GAMT.keys())
     keylist.sort()
     for key in keylist:
-      print '%s' % GAMT[key]
+      print('%s' % GAMT[key])
     sys.exit(0)
 
   # Parse the tool list
@@ -350,8 +350,8 @@ def parseConfigFile(fname, Config=Config, Jobs=Jobs):
     if jobname=='MergeOutputFiles': continue
     if jobname=='GerbMergeGUI': continue
 
-    print '' # empty line before hand for readability
-    print 'Reading data from', jobname, '...'
+    print('') # empty line before hand for readability
+    print('Reading data from', jobname, '...')
 
     J = jobs.Job(jobname)
 
@@ -369,12 +369,12 @@ def parseConfigFile(fname, Config=Config, Jobs=Jobs):
         try:
           J.ExcellonDecimals = int(fname)
         except:
-          raise RuntimeError, "Excellon decimals '%s' in config file is not a valid integer" % fname
+          raise RuntimeError("Excellon decimals '%s' in config file is not a valid integer" % fname)
       elif layername=='repeat':
         try:
           J.Repeat = int(fname)
         except:
-          raise RuntimeError, "Repeat count '%s' in config file is not a valid integer" % fname
+          raise RuntimeError("Repeat count '%s' in config file is not a valid integer" % fname)
 
     for layername in CP.options(jobname):
       fname = CP.get(jobname, layername)
@@ -388,34 +388,34 @@ def parseConfigFile(fname, Config=Config, Jobs=Jobs):
 
     # Emit warnings if some layers are missing
     LL = LayerList.copy()
-    for layername in J.apxlat.keys():
-      assert LL.has_key(layername)
+    for layername in list(J.apxlat.keys()):
+      assert layername in LL
       del LL[layername]
 
     if LL:
       if errstr=='ERROR':
         do_abort=1
 
-      print '%s: Job %s is missing the following layers:' % (errstr, jobname)
-      for layername in LL.keys():
-        print '  %s' % layername
+      print('%s: Job %s is missing the following layers:' % (errstr, jobname))
+      for layername in list(LL.keys()):
+        print('  %s' % layername)
 
     # Store the job in the global Jobs dictionary, keyed by job name
     Jobs[jobname] = J
 
   if do_abort:
-    raise RuntimeError, 'Exiting since jobs are missing layers. Set AllowMissingLayers=1\nto override.'
+    raise RuntimeError('Exiting since jobs are missing layers. Set AllowMissingLayers=1\nto override.')
 
 if __name__=="__main__":
   CP = parseConfigFile(sys.argv[1])
-  print Config
+  print(Config)
   sys.exit(0)
 
   if 0:
-    for key, val in CP.defaults().items():
-      print '%s: %s' % (key,val)
+    for key, val in list(CP.defaults().items()):
+      print('%s: %s' % (key,val))
 
     for section in CP.sections():
-      print '[%s]' % section
+      print('[%s]' % section)
       for opt in CP.options(section):
-        print '  %s=%s' % (opt, CP.get(section, opt))
+        print('  %s=%s' % (opt, CP.get(section, opt)))
diff --git a/gerbmerge/drillcluster.py b/gerbmerge/drillcluster.py
index cf9b15a..f8282eb 100644
--- a/gerbmerge/drillcluster.py
+++ b/gerbmerge/drillcluster.py
@@ -34,7 +34,7 @@ def cluster(drills, tolerance, debug = _DEBUG):
     debug_print("Clustering drill sizes ...", True)
 
     # Loop through all drill sizes
-    sizes = drills.keys()
+    sizes = list(drills.keys())
     sizes.sort()
     for size in sizes:
         
@@ -106,7 +106,7 @@ def remap(jobs, globalToolMap, debug = _DEBUG):
         debug_print( str(job.xcommands) )
         new_tools = {}
         new_commands = {}
-        for tool, diam in job.xdiam.items():
+        for tool, diam in list(job.xdiam.items()):
         
             ##debug_print("\n  Current tool: " + tool + " (" + str_d(diam) + ")")
         
@@ -147,9 +147,9 @@ def debug_print(text, status = False, newLine = True):
     
     if _DEBUG or (status and _STATUS):
         if newLine:
-            print " ", text
+            print(" ", text)
         else:
-            print " ", text,
+            print(" ", text, end=' ')
             
 def str_d(drills):
     """
@@ -180,7 +180,7 @@ def drillsToString(drills):
     """
     string = ""
     
-    drills = drills.items()
+    drills = list(drills.items())
     drills.sort()
     for size, drill in drills:
         string += drill + " = " + str_d(size) + "\n  "
@@ -194,7 +194,7 @@ def drillsToString(drills):
 if __name__=="__main__":
   import random
   
-  print "  Clustering random drills..."
+  print("  Clustering random drills...")
 
   old = {}
   tool_num = 0
diff --git a/gerbmerge/fabdrawing.py b/gerbmerge/fabdrawing.py
index ea2d2bb..498f890 100644
--- a/gerbmerge/fabdrawing.py
+++ b/gerbmerge/fabdrawing.py
@@ -25,7 +25,7 @@ def writeDrillHits(fid, Place, Tools):
     try:
       size = config.GlobalToolMap[tool]
     except:
-      raise RuntimeError, "INTERNAL ERROR: Tool code %s not found in global tool list" % tool
+      raise RuntimeError("INTERNAL ERROR: Tool code %s not found in global tool list" % tool)
 
     #for row in Layout:
     #  row.writeDrillHits(fid, size, toolNumber)
@@ -157,9 +157,9 @@ def writeUserText(fid, X, Y):
   if not fname: return
 
   try:
-    tfile = file(fname, 'rt')
-  except Exception, detail:
-    raise RuntimeError, "Could not open fabrication drawing text file '%s':\n  %s" % (fname,str(detail))
+    tfile = open(fname, 'rt')
+  except Exception as detail:
+    raise RuntimeError("Could not open fabrication drawing text file '%s':\n  %s" % (fname,str(detail)))
 
   lines = tfile.readlines()
   tfile.close()
@@ -170,7 +170,7 @@ def writeUserText(fid, X, Y):
 
   for line in lines:
     # Get rid of CR
-    line = string.replace(line, '\x0D', '')
+    line = str.replace(line, '\x0D', '')
 
     # Chop off \n
     #if line[-1] in string.whitespace:
diff --git a/gerbmerge/geometry.py b/gerbmerge/geometry.py
index 4d20d50..63e57d6 100644
--- a/gerbmerge/geometry.py
+++ b/gerbmerge/geometry.py
@@ -15,7 +15,7 @@ import math
 
 # Ensure all list elements are unique
 def uniqueify(L):
-  return {}.fromkeys(L).keys()
+  return list({}.fromkeys(L).keys())
 
 # This function rounds an (X,Y) point to integer co-ordinates
 def roundPoint(pt):
@@ -343,4 +343,4 @@ if __name__=="__main__":
   assert isRect1InRect2( (100,100,500,500), (0,600,300,300) ) == False
   assert isRect1InRect2( (100,100,500,500), (0,0,500,500) )   == True
 
-  print 'All tests pass'
+  print('All tests pass')
diff --git a/gerbmerge/gerbmerge.py b/gerbmerge/gerbmerge.py
index cb83bf0..bfdc3e4 100755
--- a/gerbmerge/gerbmerge.py
+++ b/gerbmerge/gerbmerge.py
@@ -60,8 +60,7 @@ config.PlacementFile = None
 GUI = None
 
 def usage():
-  print \
-"""
+  print("""
 Usage: gerbmerge [Options] configfile [layoutfile]
 
 Options:
@@ -89,7 +88,7 @@ the layout file (if any) is ignored.
 
 NOTE: The dimensions of each job are determined solely by the maximum extent of
 the board outline layer for each job.
-"""
+""")
   sys.exit(1)
 
 # changed these two writeGerberHeader files to take metric units (mm) into account:
@@ -146,14 +145,14 @@ G71*
 writeGerberHeader = writeGerberHeader22degrees
 
 def writeApertureMacros(fid, usedDict):
-  keys = config.GAMT.keys()
+  keys = list(config.GAMT.keys())
   keys.sort()
   for key in keys:
     if key in usedDict:
       config.GAMT[key].writeDef(fid)
 
 def writeApertures(fid, usedDict):
-  keys = config.GAT.keys()
+  keys = list(config.GAT.keys())
   keys.sort()
   for key in keys:
     if key in usedDict:
@@ -254,7 +253,7 @@ def writeCropMarks(fid, drawing_code, OriginX, OriginY, MaxXExtent, MaxYExtent):
   fid.write('X%07dY%07dD01*\n' % (util.in2gerb(x+cropW), util.in2gerb(y+0.000)))
 
 def disclaimer():
-  print """
+  print("""
 ****************************************************
 *           R E A D    C A R E F U L L Y           *
 *                                                  *
@@ -279,14 +278,14 @@ def disclaimer():
 To agree to the above terms, press 'y' then Enter.
 Any other key will exit the program.
 
-"""
+""")
 
-  s = raw_input()
+  s = input()
   if s == 'y':
-    print
+    print()
     return
 
-  print "\nExiting..."
+  print("\nExiting...")
   sys.exit(0)
 
 def tile_jobs(Jobs):
@@ -318,9 +317,9 @@ def tile_jobs(Jobs):
   if not tile:
     # add metric support (1/1000 mm vs. 1/100,000 inch)
     if config.Config['measurementunits'] == 'inch':
-      raise RuntimeError, 'Panel size %.2f"x%.2f" is too small to hold jobs' % (PX,PY)
+      raise RuntimeError('Panel size %.2f"x%.2f" is too small to hold jobs' % (PX,PY))
     else:
-      raise RuntimeError, 'Panel size %.2fmmx%.2fmm is too small to hold jobs' % (PX,PY)
+      raise RuntimeError('Panel size %.2fmmx%.2fmm is too small to hold jobs' % (PX,PY))
 
   return tile
 
@@ -339,7 +338,7 @@ def merge(opts, args, gui = None):
       elif arg=='normal':
         writeGerberHeader = writeGerberHeader22degrees
       else:
-        raise RuntimeError, 'Unknown octagon format'
+        raise RuntimeError('Unknown octagon format')
     elif opt in ('--random-search',):
       config.AutoSearchType = RANDOM_SEARCH
     elif opt in ('--full-search',):
@@ -358,10 +357,10 @@ def merge(opts, args, gui = None):
     elif opt in ('-s', '--skipdisclaimer'):
       skipDisclaimer = 1
     else:
-      raise RuntimeError, "Unknown option: %s" % opt
+      raise RuntimeError("Unknown option: %s" % opt)
 
   if len(args) > 2 or len(args) < 1:
-    raise RuntimeError, 'Invalid number of arguments'
+    raise RuntimeError('Invalid number of arguments')
 
   if (skipDisclaimer == 0):
     disclaimer()
@@ -372,7 +371,7 @@ def merge(opts, args, gui = None):
   config.parseConfigFile(args[0])
 
   # Force all X and Y coordinates positive by adding absolute value of minimum X and Y
-  for name, job in config.Jobs.iteritems():
+  for name, job in config.Jobs.items():
     min_x, min_y = job.mincoordinates()
     shift_x = shift_y = 0
     if min_x < 0: shift_x = abs(min_x)
@@ -381,31 +380,31 @@ def merge(opts, args, gui = None):
       job.fixcoordinates( shift_x, shift_y )
 
   # Display job properties                                                                
-  for job in config.Jobs.values():
-    print 'Job %s:' % job.name,
+  for job in list(config.Jobs.values()):
+    print('Job %s:' % job.name, end=' ')
     if job.Repeat > 1:
-      print '(%d instances)' % job.Repeat
+      print('(%d instances)' % job.Repeat)
     else:
-      print
-    print '  Extents: (%d,%d)-(%d,%d)' % (job.minx,job.miny,job.maxx,job.maxy)
+      print()
+    print('  Extents: (%d,%d)-(%d,%d)' % (job.minx,job.miny,job.maxx,job.maxy))
     # add metric support (1/1000 mm vs. 1/100,000 inch)
     if config.Config['measurementunits'] == 'inch':
-      print '  Size: %f" x %f"' % (job.width_in(), job.height_in())
+      print('  Size: %f" x %f"' % (job.width_in(), job.height_in()))
     else:
-      print '  Size: %5.3fmm x %5.3fmm' % (job.width_in(), job.height_in())
-    print
+      print('  Size: %5.3fmm x %5.3fmm' % (job.width_in(), job.height_in()))
+    print()
 
   # Trim drill locations and flash data to board extents
   if config.TrimExcellon:
     updateGUI("Trimming Excellon data...")
-    print 'Trimming Excellon data to board outlines ...'
-    for job in config.Jobs.values():
+    print('Trimming Excellon data to board outlines ...')
+    for job in list(config.Jobs.values()):
       job.trimExcellon()
 
   if config.TrimGerber:
     updateGUI("Trimming Gerber data...")
-    print 'Trimming Gerber data to board outlines ...'
-    for job in config.Jobs.values():
+    print('Trimming Gerber data to board outlines ...')
+    for job in list(config.Jobs.values()):
       job.trimGerber()
 
   # We start origin at (0.1", 0.1") just so we don't get numbers close to 0
@@ -416,7 +415,7 @@ def merge(opts, args, gui = None):
   # Read the layout file and construct the nested list of jobs. If there
   # is no layout file, do auto-layout.
   updateGUI("Performing layout...")
-  print 'Performing layout ...'
+  print('Performing layout ...')
   if len(args) > 1:
     Layout = parselayout.parseLayoutFile(args[1])
 
@@ -439,7 +438,7 @@ def merge(opts, args, gui = None):
     Place.addFromFile(config.PlacementFile, config.Jobs)
   else:
     # Do an automatic layout based on our tiling algorithm.
-    tile = tile_jobs(config.Jobs.values())
+    tile = tile_jobs(list(config.Jobs.values()))
 
     Place = placement.Placement()
     Place.addFromTiling(tile, OriginX + config.Config['leftmargin'], OriginY + config.Config['bottommargin'])
@@ -491,9 +490,9 @@ def merge(opts, args, gui = None):
     drawing_code1 = aptable.addToApertureTable(AP)
 
   updateGUI("Writing merged files...")
-  print 'Writing merged output files ...'
+  print('Writing merged output files ...')
 
-  for layername in config.LayerList.keys():
+  for layername in list(config.LayerList.keys()):
     lname = layername
     if lname[0]=='*':
       lname = lname[1:]
@@ -504,7 +503,7 @@ def merge(opts, args, gui = None):
       fullname = 'merged.%s.ger' % lname
     OutputFiles.append(fullname)
     #print 'Writing %s ...' % fullname
-    fid = file(fullname, 'wt')
+    fid = open(fullname, 'wt')
     writeGerberHeader(fid)
     
     # Determine which apertures and macros are truly needed
@@ -516,12 +515,12 @@ def merge(opts, args, gui = None):
       apmUsedDict.update(apmd)
 
     # Increase aperature sizes to match minimum feature dimension                         
-    if config.MinimumFeatureDimension.has_key(layername):
+    if layername in config.MinimumFeatureDimension:
     
-      print '  Thickening', lname, 'feature dimensions ...'
+      print('  Thickening', lname, 'feature dimensions ...')
       
       # Fix each aperture used in this layer
-      for ap in apUsedDict.keys():
+      for ap in list(apUsedDict.keys()):
         new = config.GAT[ap].getAdjusted( config.MinimumFeatureDimension[layername] )
         if not new: ## current aperture size met minimum requirement
           continue
@@ -595,7 +594,7 @@ def merge(opts, args, gui = None):
   if fullname and fullname.lower() != "none":
     OutputFiles.append(fullname)
     #print 'Writing %s ...' % fullname
-    fid = file(fullname, 'wt')
+    fid = open(fullname, 'wt')
     writeGerberHeader(fid)
 
     # Write width-1 aperture to file
@@ -624,7 +623,7 @@ def merge(opts, args, gui = None):
   if fullname and fullname.lower() != "none":
     OutputFiles.append(fullname)
     #print 'Writing %s ...' % fullname
-    fid = file(fullname, 'wt')
+    fid = open(fullname, 'wt')
     writeGerberHeader(fid)
 
     # Write width-1 aperture to file
@@ -644,19 +643,19 @@ def merge(opts, args, gui = None):
   # of tools.
   if 0:
     Tools = {}
-    for job in config.Jobs.values():
-      for key in job.xcommands.keys():
+    for job in list(config.Jobs.values()):
+      for key in list(job.xcommands.keys()):
         Tools[key] = 1
 
-    Tools = Tools.keys()
+    Tools = list(Tools.keys())
     Tools.sort()
   else:
     toolNum = 0
 
     # First construct global mapping of diameters to tool numbers
-    for job in config.Jobs.values():
-      for tool,diam in job.xdiam.items():
-        if config.GlobalToolRMap.has_key(diam):
+    for job in list(config.Jobs.values()):
+      for tool,diam in list(job.xdiam.items()):
+        if diam in config.GlobalToolRMap:
           continue
 
         toolNum += 1
@@ -665,24 +664,24 @@ def merge(opts, args, gui = None):
     # Cluster similar tool sizes to reduce number of drills
     if config.Config['drillclustertolerance'] > 0:
       config.GlobalToolRMap = drillcluster.cluster( config.GlobalToolRMap, config.Config['drillclustertolerance'] )
-      drillcluster.remap( Place.jobs, config.GlobalToolRMap.items() )
+      drillcluster.remap( Place.jobs, list(config.GlobalToolRMap.items()) )
 
     # Now construct mapping of tool numbers to diameters
-    for diam,tool in config.GlobalToolRMap.items():
+    for diam,tool in list(config.GlobalToolRMap.items()):
       config.GlobalToolMap[tool] = diam
 
     # Tools is just a list of tool names
-    Tools = config.GlobalToolMap.keys()
+    Tools = list(config.GlobalToolMap.keys())
     Tools.sort()   
 
   fullname = config.Config['fabricationdrawingfile']
   if fullname and fullname.lower() != 'none':
     if len(Tools) > strokes.MaxNumDrillTools:
-      raise RuntimeError, "Only %d different tool sizes supported for fabrication drawing." % strokes.MaxNumDrillTools
+      raise RuntimeError("Only %d different tool sizes supported for fabrication drawing." % strokes.MaxNumDrillTools)
 
     OutputFiles.append(fullname)
     #print 'Writing %s ...' % fullname
-    fid = file(fullname, 'wt')
+    fid = open(fullname, 'wt')
     writeGerberHeader(fid)
     writeApertures(fid, {drawing_code1: None})
     fid.write('%s*\n' % drawing_code1)    # Choose drawing aperture
@@ -699,7 +698,7 @@ def merge(opts, args, gui = None):
     fullname = 'merged.drills.xln'
   OutputFiles.append(fullname)
   #print 'Writing %s ...' % fullname
-  fid = file(fullname, 'wt')
+  fid = open(fullname, 'wt')
 
   writeExcellonHeader(fid)
 
@@ -709,7 +708,7 @@ def merge(opts, args, gui = None):
     try:
       size = config.GlobalToolMap[tool]
     except:
-      raise RuntimeError, "INTERNAL ERROR: Tool code %s not found in global tool map" % tool
+      raise RuntimeError("INTERNAL ERROR: Tool code %s not found in global tool map" % tool)
     writeExcellonTool(fid, tool, size)
 
   writeExcellonHeaderEnd(fid)
@@ -755,57 +754,57 @@ def merge(opts, args, gui = None):
     fullname = 'merged.toollist.drl'
   OutputFiles.append(fullname)
   #print 'Writing %s ...' % fullname
-  fid = file(fullname, 'wt')
+  fid = open(fullname, 'wt')
 
-  print '-'*50
+  print('-'*50)
   # add metric support (1/1000 mm vs. 1/100,000 inch)
   if config.Config['measurementunits'] == 'inch':
-    print '     Job Size : %f" x %f"' % (MaxXExtent-OriginX, MaxYExtent-OriginY)
-    print '     Job Area : %.2f sq. in.' % totalarea
+    print('     Job Size : %f" x %f"' % (MaxXExtent-OriginX, MaxYExtent-OriginY))
+    print('     Job Area : %.2f sq. in.' % totalarea)
   else:
-    print '     Job Size : %.2fmm x %.2fmm' % (MaxXExtent-OriginX, MaxYExtent-OriginY)
-    print '     Job Area : %.0f mm2' % totalarea
+    print('     Job Size : %.2fmm x %.2fmm' % (MaxXExtent-OriginX, MaxYExtent-OriginY))
+    print('     Job Area : %.0f mm2' % totalarea)
 
-  print '   Area Usage : %.1f%%' % (jobarea/totalarea*100)
-  print '   Drill hits : %d' % drillhits
+  print('   Area Usage : %.1f%%' % (jobarea/totalarea*100))
+  print('   Drill hits : %d' % drillhits)
   if config.Config['measurementunits'] == 'inch':
-    print 'Drill density : %.1f hits/sq.in.' % (drillhits/totalarea)
+    print('Drill density : %.1f hits/sq.in.' % (drillhits/totalarea))
   else:
-    print 'Drill density : %.2f hits/cm2' % (100*drillhits/totalarea)
+    print('Drill density : %.2f hits/cm2' % (100*drillhits/totalarea))
 
-  print '\nTool List:'
+  print('\nTool List:')
   smallestDrill = 999.9
   for tool in Tools:
     if ToolStats[tool]:
       if config.Config['measurementunits'] == 'inch':
         fid.write('%s %.4fin\n' % (tool, config.GlobalToolMap[tool]))
-        print '  %s %.4f" %5d hits' % (tool, config.GlobalToolMap[tool], ToolStats[tool])
+        print('  %s %.4f" %5d hits' % (tool, config.GlobalToolMap[tool], ToolStats[tool]))
       else:
         fid.write('%s %.4fmm\n' % (tool, config.GlobalToolMap[tool]))
-        print '  %s %.4fmm %5d hits' % (tool, config.GlobalToolMap[tool], ToolStats[tool])
+        print('  %s %.4fmm %5d hits' % (tool, config.GlobalToolMap[tool], ToolStats[tool]))
       smallestDrill = min(smallestDrill, config.GlobalToolMap[tool])
 
   fid.close()
   if config.Config['measurementunits'] == 'inch':
-    print "Smallest Tool: %.4fin" % smallestDrill
+    print("Smallest Tool: %.4fin" % smallestDrill)
   else:
-    print "Smallest Tool: %.4fmm" % smallestDrill
+    print("Smallest Tool: %.4fmm" % smallestDrill)
 
-  print
-  print 'Output Files :'
+  print()
+  print('Output Files :')
   for f in OutputFiles:
-    print '  ', f
+    print('  ', f)
 
   if (MaxXExtent-OriginX)>config.Config['panelwidth'] or (MaxYExtent-OriginY)>config.Config['panelheight']:
-    print '*'*75
-    print '*'
+    print('*'*75)
+    print('*')
     # add metric support (1/1000 mm vs. 1/100,000 inch)
     if config.Config['measurementunits'] == 'inch':
-      print '* ERROR: Merged job exceeds panel dimensions of %.1f"x%.1f"' % (config.Config['panelwidth'],config.Config['panelheight'])
+      print('* ERROR: Merged job exceeds panel dimensions of %.1f"x%.1f"' % (config.Config['panelwidth'],config.Config['panelheight']))
     else:
-      print '* ERROR: Merged job exceeds panel dimensions of %.1fmmx%.1fmm' % (config.Config['panelwidth'],config.Config['panelheight'])
-    print '*'
-    print '*'*75
+      print('* ERROR: Merged job exceeds panel dimensions of %.1fmmx%.1fmm' % (config.Config['panelwidth'],config.Config['panelheight']))
+    print('*')
+    print('*'*75)
     sys.exit(1)
 
   # Done!
@@ -826,19 +825,19 @@ def main():
     if opt in ('-h', '--help'):
       usage()
     elif opt in ('-v', '--version'):
-      print """
+      print("""
 GerbMerge Version %s  --  Combine multiple Gerber/Excellon files
 
 This program is licensed under the GNU General Public License (GPL)
 Version 3. See LICENSE file or http://www.fsf.org for details of this license.
 
 ProvideYourOwn - http://provideyourown.com
-""" % (__version__)
+""" % (__version__))
       sys.exit(0)
     elif opt in ('--octagons', '--random-search','--full-search','--rs-fsjobs','--place-file','--no-trim-gerber','--no-trim-excellon', '--search-timeout', '-s', '--skipdisclaimer'):
       pass ## arguments are valid
     else:
-      raise RuntimeError, "Unknown option: %s" % opt
+      raise RuntimeError("Unknown option: %s" % opt)
 
   if len(args) > 2 or len(args) < 1:
     usage()
diff --git a/gerbmerge/jobs.py b/gerbmerge/jobs.py
index efe969c..0f4e853 100644
--- a/gerbmerge/jobs.py
+++ b/gerbmerge/jobs.py
@@ -18,7 +18,7 @@ http://github.com/unwireddevices/gerbmerge
 import sys
 import re
 import string
-import __builtin__
+import builtins
 import copy
 import types
 
@@ -235,17 +235,17 @@ class Job:
     self.maxy += y_shift
 
     # Shift all commands
-    for layer, command in self.commands.iteritems():
+    for layer, command in self.commands.items():
     
       # Loop through each command in each layer
       for index in range( len(command) ):
         c = command[index]
         
         # Shift X and Y coordinate of command
-        if type(c) == types.TupleType:                      ## ensure that command is of type tuple
+        if type(c) == tuple:                      ## ensure that command is of type tuple
           command_list = list(c)                            ## convert tuple to list
-          if  (type( command_list[0] ) == types.IntType) \
-          and (type( command_list[1] ) == types.IntType):  ## ensure that first two elemenst are integers
+          if  (type( command_list[0] ) == int) \
+          and (type( command_list[1] ) == int):  ## ensure that first two elemenst are integers
             command_list[0] += x_shift
             command_list[1] += y_shift
           command[index] = tuple(command_list)              ## convert list back to tuple
@@ -253,7 +253,7 @@ class Job:
       self.commands[layer] = command                        ## set modified command
      
     # Shift all excellon commands
-    for tool, command in self.xcommands.iteritems():
+    for tool, command in self.xcommands.items():
     
       # Loop through each command in each layer
       for index in range( len(command) ):
@@ -261,12 +261,12 @@ class Job:
         
         # Shift X and Y coordinate of command
         command_list = list(c)                              ## convert tuple to list
-        if ( type( command_list[0] ) == types.IntType ) \
-        and ( type( command_list[1] ) == types.IntType ):  ## ensure that first two elemenst are integers
+        if ( type( command_list[0] ) == int ) \
+        and ( type( command_list[1] ) == int ):  ## ensure that first two elemenst are integers
           command_list[0] += x_shift / 10
           command_list[1] += y_shift / 10
-          if ( type( command_list[2] ) == types.IntType ) \
-          and ( type( command_list[3] ) == types.IntType ):  ## ensure that first two elemenst are integerslen(command_list) == 4:
+          if ( type( command_list[2] ) == int ) \
+          and ( type( command_list[3] ) == int ):  ## ensure that first two elemenst are integerslen(command_list) == 4:
             # G85 command, need to shift the second pair of xy, too.
             command_list[2] += x_shift / 10
             command_list[3] += y_shift / 10
@@ -286,7 +286,7 @@ class Job:
 
     #print 'Reading data from %s ...' % fullname
 
-    fid = file(fullname, 'rt')
+    fid = open(fullname, 'rt')
     currtool = None
 
     self.apxlat[layername] = {}
@@ -338,7 +338,7 @@ class Job:
 
     for line in fid:
       # Get rid of CR characters (0x0D) and leading/trailing blanks
-      line = string.replace(line, '\x0D', '').strip()
+      line = str.replace(line, '\x0D', '').strip()
 
       # Old location of format_pat search. Now moved down into the sub-line parse loop below.
 
@@ -354,11 +354,11 @@ class Job:
       match = apdef_pat.match(line)
       if match:
         if currtool:
-          raise RuntimeError, "File %s has an aperture definition that comes after drawing commands." % fullname
+          raise RuntimeError("File %s has an aperture definition that comes after drawing commands." % fullname)
 
         A = aptable.parseAperture(line, self.apmxlat[layername])
         if not A:
-          raise RuntimeError, "Unknown aperture definition in file %s" % fullname
+          raise RuntimeError("Unknown aperture definition in file %s" % fullname)
         # [andreika]: apply units
         if type(A.dimx) == float or type(A.dimx) == int:
           A.dimx *= units_div
@@ -366,11 +366,11 @@ class Job:
           A.dimy *= units_div
 
         hash = A.hash()
-        if not RevGAT.has_key(hash):
+        if hash not in RevGAT:
           #print line
           #print self.apmxlat
           #print RevGAT
-          raise RuntimeError, 'File %s has aperture definition "%s" not in global aperture table.' % (fullname, hash)
+          raise RuntimeError('File %s has aperture definition "%s" not in global aperture table.' % (fullname, hash))
 
         # This says that all draw commands with this aperture code will
         # be replaced by aperture self.apxlat[layername][code].
@@ -402,7 +402,7 @@ class Job:
           continue # ignore it so func doesn't choke on it
 
       if line[:3] == '%SF': # scale factor - we will ignore it
-        print 'Scale factor parameter ignored: ' + line
+        print('Scale factor parameter ignored: ' + line)
         continue
       
 # end basic diptrace fixes
@@ -411,11 +411,11 @@ class Job:
       M = amacro.parseApertureMacro(line,fid)
       if M:
         if currtool:
-          raise RuntimeError, "File %s has an aperture macro definition that comes after drawing commands." % fullname
+          raise RuntimeError("File %s has an aperture macro definition that comes after drawing commands." % fullname)
 
         hash = M.hash()
-        if not RevGAMT.has_key(hash):
-          raise RuntimeError, 'File %s has aperture macro definition not in global aperture macro table:\n%s' % (fullname, hash)
+        if hash not in RevGAMT:
+          raise RuntimeError('File %s has aperture macro definition not in global aperture macro table:\n%s' % (fullname, hash))
 
         # This says that all aperture definition commands that reference this macro name
         # will be replaced by aperture macro name self.apmxlat[layername][macroname].
@@ -445,9 +445,9 @@ class Job:
               continue
 
             if item[0]=='T':      # omit trailing zeroes
-              raise RuntimeError, "Trailing zeroes not supported in RS274X files"
+              raise RuntimeError("Trailing zeroes not supported in RS274X files")
             if item[0]=='I':      # incremental co-ordinates
-              raise RuntimeError, "Incremental co-ordinates not supported in RS274X files"
+              raise RuntimeError("Incremental co-ordinates not supported in RS274X files")
 
             if item[0]=='N':      # Maximum digits for N* commands...ignore it
               continue
@@ -508,7 +508,7 @@ class Job:
 
             continue
 
-          raise RuntimeError, "G-Code 'G%02d' is not supported" % gcode
+          raise RuntimeError("G-Code 'G%02d' is not supported" % gcode)
 
         # See if this is a tool change (aperture change) command
         match = tool_pat.match(sub_line)
@@ -541,8 +541,8 @@ class Job:
             continue
 
           # Map it using our translation table
-          if not self.apxlat[layername].has_key(currtool):
-            raise RuntimeError, 'File %s has tool change command "%s" with no corresponding translation' % (fullname, currtool)
+          if currtool not in self.apxlat[layername]:
+            raise RuntimeError('File %s has tool change command "%s" with no corresponding translation' % (fullname, currtool))
 
           currtool = self.apxlat[layername][currtool]
 
@@ -561,17 +561,17 @@ class Job:
         match = drawXY_pat.match(sub_line)
         isLastShorthand = False    # By default assume we don't make use of last_x and last_y
         if match:
-          x, y, d = map(__builtin__.int, match.groups())
+          x, y, d = list(map(builtins.int, match.groups()))
         else:
           match = drawX_pat.match(sub_line)
           if match:
-            x, d = map(__builtin__.int, match.groups())
+            x, d = list(map(builtins.int, match.groups()))
             y = last_y
             isLastShorthand = True  # Indicate we're making use of last_x/last_y
           else:
             match = drawY_pat.match(sub_line)
             if match:
-              y, d = map(__builtin__.int, match.groups())
+              y, d = list(map(builtins.int, match.groups()))
               x = last_x
               isLastShorthand = True  # Indicate we're making use of last_x/last_y
 
@@ -579,17 +579,17 @@ class Job:
         if match is None:
           match = cdrawXY_pat.match(sub_line)
           if match:
-            x, y, I, J, d = map(__builtin__.int, match.groups())
+            x, y, I, J, d = list(map(builtins.int, match.groups()))
           else:
             match = cdrawX_pat.match(sub_line)
             if match:
-              x, I, J, d = map(__builtin__.int, match.groups())
+              x, I, J, d = list(map(builtins.int, match.groups()))
               y = last_y
               isLastShorthand = True  # Indicate we're making use of last_x/last_y
             else:
               match = cdrawY_pat.match(sub_line)
               if match:
-                y, I, J, d = map(__builtin__.int, match.groups())
+                y, I, J, d = list(map(builtins.int, match.groups()))
                 x = last_x
                 isLastShorthand = True  # Indicate we're making use of last_x/last_y
 
@@ -601,7 +601,7 @@ class Job:
             if (d != 2) and (last_gmode != 36):
               # [andreika]: check for fill mode more accurately
               if not in_fill_mode:
-                  raise RuntimeError, 'File %s has draw command %s with no aperture chosen' % (fullname, sub_line)
+                  raise RuntimeError('File %s has draw command %s with no aperture chosen' % (fullname, sub_line))
 
           # Save last_x/y BEFORE scaling to 2.5 format else subsequent single-ordinate
           # flashes (e.g., Y with no X) will be scaled twice!
@@ -649,7 +649,7 @@ class Job:
           if match:
             break
         else:
-          raise RuntimeError, 'File %s has uninterpretable line:\n  %s' % (fullname, line)
+          raise RuntimeError('File %s has uninterpretable line:\n  %s' % (fullname, line))
 
         sub_line = sub_line[match.end():]
       # end while still things to match on this line
@@ -657,13 +657,13 @@ class Job:
 
     fid.close()
     if 0:
-      print layername
-      print self.commands[layername]
+      print(layername)
+      print(self.commands[layername])
 
   def parseExcellon(self, fullname):
     #print 'Reading data from %s ...' % fullname
 
-    fid = file(fullname, 'rt')
+    fid = open(fullname, 'rt')
     currtool = None
     suppress_leading = True     # Suppress leading zeros by default, equivalent to 'INCH,TZ'
 
@@ -706,14 +706,14 @@ class Job:
           V.append(None)
       return tuple(V)
 
-    for line in fid.xreadlines():
+    for line in fid:
       # Get rid of CR characters
-      line = string.replace(line, '\x0D', '')
+      line = str.replace(line, '\x0D', '')
 
 # add support for DipTrace
       if line[:6]=='METRIC':
         if (config.Config['measurementunits'] == 'inch'):
-          raise RuntimeError, "File %s units do match config file" % fullname
+          raise RuntimeError("File %s units do match config file" % fullname)
         else:
         #print "ignoring METRIC directive: " + line
           continue # ignore it so func doesn't choke on it
@@ -746,14 +746,14 @@ class Job:
         try:
           diam = float(diam)
         except:
-          raise RuntimeError, "File %s has illegal tool diameter '%s'" % (fullname, diam)
+          raise RuntimeError("File %s has illegal tool diameter '%s'" % (fullname, diam))
 
         # Canonicalize tool number because Protel (of course) sometimes specifies it
         # as T01 and sometimes as T1. We canonicalize to T01.
         currtool = 'T%02d' % int(currtool[1:])
 
-        if self.xdiam.has_key(currtool):
-          raise RuntimeError, "File %s defines tool %s more than once" % (fullname, currtool)
+        if currtool in self.xdiam:
+          raise RuntimeError("File %s defines tool %s more than once" % (fullname, currtool))
         self.xdiam[currtool] = diam
         continue
 
@@ -779,13 +779,13 @@ class Job:
             try:
               diam = self.ToolList[currtool]
             except:
-              raise RuntimeError, "File %s uses tool code %s that is not defined in the job's tool list" % (fullname, currtool)
+              raise RuntimeError("File %s uses tool code %s that is not defined in the job's tool list" % (fullname, currtool))
           else:
             try:
               diam = config.DefaultToolList[currtool]
             except:
               #print config.DefaultToolList
-              raise RuntimeError, "File %s uses tool code %s that is not defined in default tool list" % (fullname, currtool)
+              raise RuntimeError("File %s uses tool code %s that is not defined in default tool list" % (fullname, currtool))
 
         self.xdiam[currtool] = diam
         continue
@@ -811,7 +811,7 @@ class Job:
           
       if match:
         if currtool is None:
-          raise RuntimeError, 'File %s has plunge command without previous tool selection' % fullname
+          raise RuntimeError('File %s has plunge command without previous tool selection' % fullname)
 
         try:
           self.xcommands[currtool].append((x,y,stop_x,stop_y))
@@ -827,10 +827,10 @@ class Job:
         if pat.match(line):
           break
       else:
-        raise RuntimeError, 'File %s has uninterpretable line:\n  %s' % (fullname, line)
+        raise RuntimeError('File %s has uninterpretable line:\n  %s' % (fullname, line))
 
   def hasLayer(self, layername):
-    return self.commands.has_key(layername)
+    return layername in self.commands
 
   def writeGerber(self, fid, layername, Xoff, Yoff):
     "Write out the data such that the lower-left corner of this job is at the given (X,Y) position, in inches"
@@ -858,7 +858,7 @@ class Job:
     # due to panelizing.
     fid.write('X%07dY%07dD02*\n' % (X, Y))
     for cmd in self.commands[layername]:
-      if type(cmd) is types.TupleType:
+      if type(cmd) is tuple:
         if len(cmd)==3:
           x, y, d = cmd
           fid.write('X%07dY%07dD%02d*\n' % (x+DX, y+DY, d))
@@ -877,7 +877,7 @@ class Job:
   def findTools(self, diameter):
     "Find the tools, if any, with the given diameter in inches. There may be more than one!"
     L = []
-    for tool, diam in self.xdiam.items():
+    for tool, diam in list(self.xdiam.items()):
       if diam==diameter:
         L.append(tool)
     return L
@@ -927,7 +927,7 @@ class Job:
 
     # Boogie
     for ltool in ltools:
-      if self.xcommands.has_key(ltool):
+      if ltool in self.xcommands:
         for cmd in self.xcommands[ltool]:
           x, y, stop_x, stop_y = cmd
           new_x = x+DX
@@ -965,7 +965,7 @@ class Job:
     ltools = self.findTools(diameter)
 
     for ltool in ltools:
-      if self.xcommands.has_key(ltool):
+      if ltool in self.xcommands:
         for cmd in self.xcommands[ltool]:
           x, y, stop_x, stop_y = cmd
           # add metric support (1/1000 mm vs. 1/100,000 inch)
@@ -979,7 +979,7 @@ class Job:
 
     GAT=config.GAT
 
-    if self.apertures.has_key(layername):
+    if layername in self.apertures:
       apdict = {}.fromkeys(self.apertures[layername])
       apmlist = [GAT[ap].dimx for ap in self.apertures[layername] if GAT[ap].apname=='Macro']
       apmdict = {}.fromkeys(apmlist)
@@ -990,8 +990,8 @@ class Job:
 
   def makeLocalApertureCode(self, layername, AP):
     "Find or create a layer-specific aperture code to represent the global aperture given"
-    if AP.code not in self.apxlat[layername].values():
-      lastCode = aptable.findHighestApertureCode(self.apxlat[layername].keys())
+    if AP.code not in list(self.apxlat[layername].values()):
+      lastCode = aptable.findHighestApertureCode(list(self.apxlat[layername].keys()))
       localCode = 'D%d' % (lastCode+1)
       self.apxlat[layername][localCode] = AP.code
 
@@ -1008,7 +1008,7 @@ class Job:
     lastAperture = None
 
     for cmd in self.commands[layername]:
-      if type(cmd) == types.TupleType:
+      if type(cmd) == tuple:
         # It is a data command: tuple (X, Y, D), all integers, or (X, Y, I, J, D), all integers.
         if len(cmd)==3:
           x, y, d = cmd
@@ -1180,12 +1180,12 @@ class Job:
     self.commands[layername] = newcmds
 
   def trimGerber(self):
-    for layername in self.commands.keys():
+    for layername in list(self.commands.keys()):
       self.trimGerberLayer(layername)
 
   def trimExcellon(self):
     "Remove plunge commands that are outside job dimensions"
-    keys = self.xcommands.keys()
+    keys = list(self.xcommands.keys())
     for toolname in keys:
       # Remember Excellon is 2.4 format while Gerber data is 2.5 format
       validList = [tup for tup in self.xcommands[toolname]
@@ -1390,10 +1390,10 @@ def rotateJob(job, degrees = 90, flip = 0, firstpass = True):
   # those apertures which have an orientation: rectangles, ovals, and macros.
 
   ToolChangeReplace = {}
-  for layername in job.apxlat.keys():
+  for layername in list(job.apxlat.keys()):
     J.apxlat[layername] = {}
 
-    for ap in job.apxlat[layername].keys():
+    for ap in list(job.apxlat[layername].keys()):
       code = job.apxlat[layername][ap]
       A = GAT[code]
 
@@ -1438,18 +1438,18 @@ def rotateJob(job, degrees = 90, flip = 0, firstpass = True):
     offset = 0
   else:
     offset = job.maxy-job.miny
-  for layername in job.commands.keys():
+  for layername in list(job.commands.keys()):
     J.commands[layername] = []
     J.apertures[layername] = []
 
     for cmd in job.commands[layername]:
       # Is it a drawing command?
-      if type(cmd) is types.TupleType:
+      if type(cmd) is tuple:
         if len(cmd)==3:
-          x, y, d = map(__builtin__.int, cmd)
+          x, y, d = list(map(builtins.int, cmd))
           II=JJ=None
         else:
-          x, y, II, JJ, d, signed = map(__builtin__.int, cmd)   # J is already used as Job object
+          x, y, II, JJ, d, signed = list(map(builtins.int, cmd))   # J is already used as Job object
       else:
         # No, must be a string indicating aperture change, G-code, or RS274-X command.
         if cmd[0] in ('G', '%'):
@@ -1497,13 +1497,13 @@ def rotateJob(job, degrees = 90, flip = 0, firstpass = True):
         J.commands[layername].append((newx,newy,d))
 
     if 0:
-      print job.minx, job.miny, offset
-      print layername
-      print J.commands[layername]
+      print(job.minx, job.miny, offset)
+      print(layername)
+      print(J.commands[layername])
 
   # Finally, rotate drills. Offset is in hundred-thousandths (2.5) while Excellon
   # data is in 2.4 format.
-  for tool in job.xcommands.keys():
+  for tool in list(job.xcommands.keys()):
     J.xcommands[tool] = []
 
     for x,y,stop_x,stop_y in job.xcommands[tool]:
diff --git a/gerbmerge/makestroke.py b/gerbmerge/makestroke.py
index 551ef7f..4883eeb 100644
--- a/gerbmerge/makestroke.py
+++ b/gerbmerge/makestroke.py
@@ -93,7 +93,7 @@ def writeChar(fid, c, X, Y, degrees):
   try:
     glyph = strokes.StrokeMap[c]
   except:
-    raise RuntimeError, 'No glyph for character %s' % hex(ord(c))
+    raise RuntimeError('No glyph for character %s' % hex(ord(c)))
 
   writeGlyph(fid, glyph, X, Y, degrees, c)
 
@@ -140,7 +140,7 @@ if __name__=="__main__":
   s = string.digits+string.letters+string.punctuation
   #s = "The quick brown fox jumped over the lazy dog!"
 
-  fid = file('test.ger','wt')
+  fid = open('test.ger','wt')
   fid.write("""G75*
 G70*
 %OFA0B0*%
diff --git a/gerbmerge/parselayout.py b/gerbmerge/parselayout.py
index 0a8d0e6..9bfb3fa 100644
--- a/gerbmerge/parselayout.py
+++ b/gerbmerge/parselayout.py
@@ -184,7 +184,7 @@ def findJob(jobname, rotatedFlipped, Jobs=config.Jobs):
     
                          
   try:
-    for existingjob in Jobs.keys():
+    for existingjob in list(Jobs.keys()):
       if existingjob.lower() == fullname.lower(): ## job names are case insensitive
         job = Jobs[existingjob]                 
         return jobs.JobLayout(job)
@@ -194,13 +194,13 @@ def findJob(jobname, rotatedFlipped, Jobs=config.Jobs):
   # Perhaps we just don't have a rotated or flipped job yet
   if rotatedFlipped[0] or rotatedFlipped[1]:
     try:      
-      for existingjob in Jobs.keys():
+      for existingjob in list(Jobs.keys()):
         if existingjob.lower() == jobname.lower(): ## job names are case insensitive
           job = Jobs[existingjob]
     except:
-      raise RuntimeError, "Job name '%s' not found" % jobname
+      raise RuntimeError("Job name '%s' not found" % jobname)
   else:
-    raise RuntimeError, "Job name '%s' not found" % jobname
+    raise RuntimeError("Job name '%s' not found" % jobname)
 
   # Make a rotated/flipped job
   job = jobs.rotateJob(job, rotatedFlipped[0], rotatedFlipped[1])
@@ -228,14 +228,14 @@ def parseJobSpec(spec, data):
         elif rotation == "Rotate270":
             rotated = 270
         else:
-            raise RuntimeError, "Unsupported rotation: %s" % rotation
+            raise RuntimeError("Unsupported rotation: %s" % rotation)
 
       else:
         rotated = 0
 
       return findJob(jobname, [rotated, 0])
     else:
-      raise RuntimeError, "Matrix panels not yet supported"
+      raise RuntimeError("Matrix panels not yet supported")
 
 def parseColSpec(spec, data):
   jobs = Col()
@@ -302,9 +302,9 @@ def parseLayoutFile(fname):
   """
 
   try:
-    fid = file(fname, 'rt')
-  except Exception, detail:
-    raise RuntimeError, "Unable to open layout file: %s\n  %s" % (fname, str(detail))
+    fid = open(fname, 'rt')
+  except Exception as detail:
+    raise RuntimeError("Unable to open layout file: %s\n  %s" % (fname, str(detail)))
 
   data = fid.read()
   fid.close()
@@ -312,16 +312,16 @@ def parseLayoutFile(fname):
 
   # Replace all CR's in data with nothing, to convert DOS line endings
   # to unix format (all LF's).
-  data = string.replace(data, '\x0D', '')
+  data = str.replace(data, '\x0D', '')
 
   tree = parser.parse(data)
 
   # Last element of tree is number of characters parsed
   if not tree[0]:
-    raise RuntimeError, "Layout file cannot be parsed"
+    raise RuntimeError("Layout file cannot be parsed")
 
   if tree[2] != len(data):
-    raise RuntimeError, "Parse error at character %d in layout file" % tree[2]
+    raise RuntimeError("Parse error at character %d in layout file" % tree[2])
 
   Rows = []
   for rowspec in tree[1]:
@@ -333,7 +333,7 @@ def parseLayoutFile(fname):
   return Rows
 
 if __name__=="__main__":
-  fid = file(sys.argv[1])
+  fid = open(sys.argv[1])
   testdata = fid.read()
   fid.close()
 
diff --git a/gerbmerge/placement.py b/gerbmerge/placement.py
index 1293453..407b809 100644
--- a/gerbmerge/placement.py
+++ b/gerbmerge/placement.py
@@ -52,11 +52,11 @@ class Placement:
 
   def write(self, fname):
     """Write placement to a file"""
-    fid = file(fname, 'wt')
+    fid = open(fname, 'wt')
     for job in self.jobs:
       fid.write('%s %.3f %.3f\n' % (job.job.name, job.x, job.y))
       # added; thought it would be useful to know
-      print "job locations: job - %s x,y(%f,%f)" % (job.job.name, job.x, job.y)
+      print("job locations: job - %s x,y(%f,%f)" % (job.job.name, job.x, job.y))
     fid.close()
 
   def addFromFile(self, fname, Jobs):
@@ -65,9 +65,9 @@ class Placement:
     comment = re.compile(r'\s*(?:#.+)?$')
    
     try:
-      fid = file(fname, 'rt')
+      fid = open(fname, 'rt')
     except:
-      print 'Unable to open placement file: "%s"' % fname
+      print('Unable to open placement file: "%s"' % fname)
       sys.exit(1)
 
     lines = fid.readlines()
@@ -78,7 +78,7 @@ class Placement:
 
       match = pat.match(line)
       if not match:
-        print 'Cannot interpret placement line in placement file:\n  %s' % line
+        print('Cannot interpret placement line in placement file:\n  %s' % line)
         sys.exit(1)
 
       jobname, X, Y = match.groups()
@@ -86,7 +86,7 @@ class Placement:
         X = float(X)
         Y = float(Y)
       except:
-        print 'Illegal (X,Y) co-ordinates in placement file:\n  %s' % line
+        print('Illegal (X,Y) co-ordinates in placement file:\n  %s' % line)
         sys.exit(1)
 
       # rotated or flipped
diff --git a/gerbmerge/schwartz.py b/gerbmerge/schwartz.py
index e243961..dc9f5ce 100644
--- a/gerbmerge/schwartz.py
+++ b/gerbmerge/schwartz.py
@@ -18,9 +18,9 @@ def schwartz(List, Metric):
   def pairing(element, M = Metric):
     return (M(element), element)
 
-  paired = map(pairing, List)
+  paired = list(map(pairing, List))
   paired.sort()
-  return map(stripit, paired)
+  return list(map(stripit, paired))
 
 def stripit2(pair):
   return pair[0]
@@ -31,8 +31,8 @@ def schwartz2(List, Metric):
   def pairing(element, M = Metric):
     return (M(element), element)
 
-  paired = map(pairing, List)
+  paired = list(map(pairing, List))
   paired.sort()
-  theList = map(stripit, paired)
-  theMetrics = map(stripit2, paired)
+  theList = list(map(stripit, paired))
+  theMetrics = list(map(stripit2, paired))
   return (theList, theMetrics)
diff --git a/gerbmerge/scoring.py b/gerbmerge/scoring.py
index ecb2b80..0d73659 100644
--- a/gerbmerge/scoring.py
+++ b/gerbmerge/scoring.py
@@ -177,7 +177,7 @@ def mergeLines(Lines):
 
   # Extend horizontal lines
   NewHLines = {}
-  for yval,lines in HLines.items():
+  for yval,lines in list(HLines.items()):
     # yval is the Y ordinate of this group of lines. lines is the set of all
     # lines with this Y ordinate.
     NewHLines[yval] = []
@@ -199,7 +199,7 @@ def mergeLines(Lines):
 
   # Extend vertical lines
   NewVLines = {}
-  for xval,lines in VLines.items():
+  for xval,lines in list(VLines.items()):
     # xval is the X ordinate of this group of lines. lines is the set of all
     # lines with this X ordinate.
     NewVLines[xval] = []
@@ -228,7 +228,7 @@ def mergeLines(Lines):
   # or within each other. We will have to sort all horizontal lines by their
   # Y ordinates and group them according to Y ordinates that are close enough
   # to each other.
-  yvals = HLines.keys()
+  yvals = list(HLines.keys())
   clusters = clusterOrdinates(yvals)  # A list of clustered tuples containing yvals
 
   for cluster in clusters:
@@ -240,7 +240,7 @@ def mergeLines(Lines):
     # Y ordinate. Merge them together.
     NewHLines.extend(mergeHLines(clusterLines))
 
-  xvals = VLines.keys()
+  xvals = list(VLines.keys())
   clusters = clusterOrdinates(xvals)
   for cluster in clusters:
     clusterLines = []
diff --git a/gerbmerge/tilesearch1.py b/gerbmerge/tilesearch1.py
index dc03510..e3022b7 100644
--- a/gerbmerge/tilesearch1.py
+++ b/gerbmerge/tilesearch1.py
@@ -19,11 +19,11 @@ import gerbmerge
 
 _StartTime = 0.0           # Start time of tiling
 _CkpointTime = 0.0         # Next time to print stats
-_Placements = 0L           # Number of placements attempted
-_PossiblePermutations = 0L # Number of different ways of ordering jobs
-_Permutations = 0L         # Number of different job orderings already computed
+_Placements = 0           # Number of placements attempted
+_PossiblePermutations = 0 # Number of different ways of ordering jobs
+_Permutations = 0         # Number of different job orderings already computed
 _TBestTiling = None        # Best tiling so far
-_TBestScore  = float(sys.maxint) # Smallest area so far
+_TBestScore  = float(sys.maxsize) # Smallest area so far
 _PrintStats = 1            # Print statistics every 3 seconds
 
 def printTilingStats():
@@ -42,11 +42,11 @@ def printTilingStats():
 
   # add metric support (1/1000 mm vs. 1/100,000 inch)
   if config.Config['measurementunits'] == 'inch':
-    print "\r  %5.2f%% complete / %ld/%ld Perm/Place / Smallest area: %.1f sq. in. / Best utilization: %.1f%%" % \
-        (percent, _Permutations, _Placements, area, utilization),
+    print("\r  %5.2f%% complete / %ld/%ld Perm/Place / Smallest area: %.1f sq. in. / Best utilization: %.1f%%" % \
+        (percent, _Permutations, _Placements, area, utilization), end=' ')
   else:
-    print "\r  %5.2f%% complete / %ld/%ld Perm/Place / Smallest area: %.1f sq. mm / Best utilization: %.1f%%" % \
-        (percent, _Permutations, _Placements, area, utilization),
+    print("\r  %5.2f%% complete / %ld/%ld Perm/Place / Smallest area: %.1f sq. mm / Best utilization: %.1f%%" % \
+        (percent, _Permutations, _Placements, area, utilization), end=' ')
 
 
   if gerbmerge.GUI is not None:
@@ -86,7 +86,7 @@ def _tile_search1(Jobs, TSoFar, firstAddPoint, cfg=config.Config):
   global _StartTime, _CkpointTime, _Placements, _TBestTiling, _TBestScore, _Permutations, _PrintStats
 
   if not TSoFar:
-    return (None, float(sys.maxint))
+    return (None, float(sys.maxsize))
 
   if not Jobs:
     # Update the best tiling and score. If the new tiling matches
@@ -118,12 +118,12 @@ def _tile_search1(Jobs, TSoFar, firstAddPoint, cfg=config.Config):
     remaining_jobs = Jobs[:job_ix]+Jobs[job_ix+1:]
 
     if 0:
-      print "Level %d (%s)" % (level, job.name)
+      print("Level %d (%s)" % (level, job.name))
       TSoFar.joblist()
       for J in remaining_jobs:
-          print J[2].name, ", ",
-      print
-      print '-'*75
+          print(J[2].name, ", ", end=' ')
+      print()
+      print('-'*75)
 
     # Construct add-points for the non-rotated and rotated job.
     # As an optimization, do not construct add-points for the rotated
@@ -154,7 +154,7 @@ def _tile_search1(Jobs, TSoFar, firstAddPoint, cfg=config.Config):
       # Premature prune due to not being able to put this job anywhere. We
       # have pruned off 2^M permutations where M is the length of the remaining
       # jobs.
-      _Permutations += 2L**len(remaining_jobs)
+      _Permutations += 2**len(remaining_jobs)
 
     if addpoints2:
       for ix in addpoints2:
@@ -170,7 +170,7 @@ def _tile_search1(Jobs, TSoFar, firstAddPoint, cfg=config.Config):
       # Premature prune due to not being able to put this job anywhere. We
       # have pruned off 2^M permutations where M is the length of the remaining
       # jobs.
-      _Permutations += 2L**len(remaining_jobs)
+      _Permutations += 2**len(remaining_jobs)
 
     # If we've been at this for 3 seconds, print some status information
     if _PrintStats and time.time() > _CkpointTime:
@@ -185,9 +185,9 @@ def _tile_search1(Jobs, TSoFar, firstAddPoint, cfg=config.Config):
   # end for each job in job list
 
 def factorial(N):
-  if (N <= 1): return 1L
+  if (N <= 1): return 1
 
-  prod = long(N)
+  prod = int(N)
   while (N > 2):
       N -= 1
       prod *= N
@@ -198,10 +198,10 @@ def initialize(printStats=1):
   global _StartTime, _CkpointTime, _Placements, _TBestTiling, _TBestScore, _Permutations, _PossiblePermutations, _PrintStats
 
   _PrintStats = printStats
-  _Placements = 0L
-  _Permutations = 0L
+  _Placements = 0
+  _Permutations = 0
   _TBestTiling = None
-  _TBestScore = float(sys.maxint)
+  _TBestScore = float(sys.maxsize)
 
 def tile_search1(Jobs, X, Y):
   """Wrapper around _tile_search1 to handle keyboard interrupt, etc."""
@@ -215,36 +215,36 @@ def tile_search1(Jobs, X, Y):
   # This is assuming all jobs are unique and each job has a rotation (i.e., is not
   # square). Practically, these assumptions make no difference because the software
   # currently doesn't optimize for cases of repeated jobs.
-  _PossiblePermutations = (2L**len(Jobs))*factorial(len(Jobs))
+  _PossiblePermutations = (2**len(Jobs))*factorial(len(Jobs))
   #print "Possible permutations:", _PossiblePermutations
 
-  print '='*70
-  print "Starting placement using exhaustive search."
-  print "There are %ld possible permutations..." % _PossiblePermutations,
+  print('='*70)
+  print("Starting placement using exhaustive search.")
+  print("There are %ld possible permutations..." % _PossiblePermutations, end=' ')
   if _PossiblePermutations < 1e4:
-    print "this'll take no time at all."
+    print("this'll take no time at all.")
   elif _PossiblePermutations < 1e5:
-    print "surf the web for a few minutes."
+    print("surf the web for a few minutes.")
   elif _PossiblePermutations < 1e6:
-    print "take a long lunch."
+    print("take a long lunch.")
   elif _PossiblePermutations < 1e7:
-    print "come back tomorrow."
+    print("come back tomorrow.")
   else:
-    print "don't hold your breath."
-  print "Press Ctrl-C to stop and use the best placement so far."
-  print "Estimated maximum possible utilization is %.1f%%." % (tiling.maxUtilization(Jobs)*100)
+    print("don't hold your breath.")
+  print("Press Ctrl-C to stop and use the best placement so far.")
+  print("Estimated maximum possible utilization is %.1f%%." % (tiling.maxUtilization(Jobs)*100))
 
   try:
     _tile_search1(Jobs, tiling.Tiling(X,Y), 1)
     printTilingStats()
-    print
+    print()
   except KeyboardInterrupt:
     printTilingStats()
-    print
-    print "Interrupted."
+    print()
+    print("Interrupted.")
 
   computeTime = time.time() - _StartTime
-  print "Computed %ld placements in %d seconds / %.1f placements/second" % (_Placements, computeTime, _Placements/computeTime)
-  print '='*70
+  print("Computed %ld placements in %d seconds / %.1f placements/second" % (_Placements, computeTime, _Placements/computeTime))
+  print('='*70)
 
   return _TBestTiling
diff --git a/gerbmerge/tilesearch2.py b/gerbmerge/tilesearch2.py
index ca8396f..9af1fb4 100644
--- a/gerbmerge/tilesearch2.py
+++ b/gerbmerge/tilesearch2.py
@@ -21,9 +21,9 @@ import gerbmerge
 
 _StartTime = 0.0           # Start time of tiling
 _CkpointTime = 0.0         # Next time to print stats
-_Placements = 0L           # Number of placements attempted
+_Placements = 0           # Number of placements attempted
 _TBestTiling = None        # Best tiling so far
-_TBestScore  = float(sys.maxint) # Smallest area so far
+_TBestScore  = float(sys.maxsize) # Smallest area so far
 
 def printTilingStats():
   global _CkpointTime
@@ -38,11 +38,11 @@ def printTilingStats():
 
   # add metric support (1/1000 mm vs. 1/100,000 inch)
   if config.Config['measurementunits'] == 'inch':
-    print "\r  %ld placements / Smallest area: %.1f sq. in. / Best utilization: %.1f%%" % \
-        (_Placements, area, utilization),
+    print("\r  %ld placements / Smallest area: %.1f sq. in. / Best utilization: %.1f%%" % \
+        (_Placements, area, utilization), end=' ')
   else:
-    print "\r  %ld placements / Smallest area: %.1f sq. mm / Best utilization: %.0f%%" % \
-        (_Placements, area, utilization),
+    print("\r  %ld placements / Smallest area: %.1f sq. mm / Best utilization: %.0f%%" % \
+        (_Placements, area, utilization), end=' ')
 
   if gerbmerge.GUI is not None:
     sys.stdout.flush()
@@ -64,7 +64,7 @@ def _tile_search2(Jobs, X, Y, cfg=config.Config):
   # Must escape with Ctrl-C
   while 1:
     T = tiling.Tiling(X,Y)
-    joborder = r.sample(range(N), N)
+    joborder = r.sample(list(range(N)), N)
 
     minInletSize = tiling.minDimension(Jobs)
 
@@ -127,32 +127,32 @@ def tile_search2(Jobs, X, Y):
 
   _StartTime = time.time()
   _CkpointTime = _StartTime + 3
-  _Placements = 0L
+  _Placements = 0
   _TBestTiling = None
-  _TBestScore = float(sys.maxint)
+  _TBestScore = float(sys.maxsize)
 
-  print '='*70
+  print('='*70)
   if (config.Config['searchtimeout'] > 0):
-    print "Starting random placement trials. You can press Ctrl-C to"
-    print "stop the process and use the best placement so far, or wait"
-    print "for the automatic timeout in %i seconds." % config.Config['searchtimeout']
+    print("Starting random placement trials. You can press Ctrl-C to")
+    print("stop the process and use the best placement so far, or wait")
+    print("for the automatic timeout in %i seconds." % config.Config['searchtimeout'])
   else:
-    print "Starting random placement trials. You must press Ctrl-C to"
-    print "stop the process and use the best placement so far." 
-    print "You can specify a timeout by setting 'SearchTimeout' in  Layout.cfg"
-  print "Estimated maximum possible utilization is %.1f%%." % (tiling.maxUtilization(Jobs)*100)
+    print("Starting random placement trials. You must press Ctrl-C to")
+    print("stop the process and use the best placement so far.") 
+    print("You can specify a timeout by setting 'SearchTimeout' in  Layout.cfg")
+  print("Estimated maximum possible utilization is %.1f%%." % (tiling.maxUtilization(Jobs)*100))
 
   try:
     _tile_search2(Jobs, X, Y)
     printTilingStats()
-    print
+    print()
   except KeyboardInterrupt:
     printTilingStats()
-    print
-    print "Interrupted."
+    print()
+    print("Interrupted.")
 
   computeTime = time.time() - _StartTime
-  print "Computed %ld placements in %d seconds / %.1f placements/second" % (_Placements, computeTime, _Placements/computeTime)
-  print '='*70
+  print("Computed %ld placements in %d seconds / %.1f placements/second" % (_Placements, computeTime, _Placements/computeTime))
+  print('='*70)
 
   return _TBestTiling
diff --git a/gerbmerge/tiling.py b/gerbmerge/tiling.py
index 8fc83be..16236fc 100644
--- a/gerbmerge/tiling.py
+++ b/gerbmerge/tiling.py
@@ -319,7 +319,7 @@ mirrored-L corner __  |      |
 
   def bounds(self):
     """Return 2-tuple ((minX, minY), (maxX, maxY)) of rectangular region defined by all jobs"""
-    minX = minY = float(sys.maxint)
+    minX = minY = float(sys.maxsize)
     maxX = maxY = 0.0
 
     for bl,tr,job in self.jobs:
@@ -368,7 +368,7 @@ def maxUtilization(Jobs):
 # Utility function to compute the minimum dimension along any axis of all jobs.
 # Used to remove inlets.
 def minDimension(Jobs):
-  M = float(sys.maxint)
+  M = float(sys.maxsize)
   for Xdim,Ydim,job,rjob in Jobs:
     M = min(M,Xdim)
     M = min(M,Ydim)