diff --git a/types/gas.go b/types/gas.go
index d4b63597c..24be99f3f 100644
--- a/types/gas.go
+++ b/types/gas.go
@@ -2,8 +2,10 @@ package types
 
 import ()
 
+// Gas measured by the SDK
 type Gas = int64
 
+// GasMeter interface to track gas consumption
 type GasMeter interface {
 	GasExceeded() bool
 	GasConsumed() Gas