diff --git a/firmware/pump_dac.cpp b/firmware/pump_dac.cpp
index af9db90..4ec2568 100644
--- a/firmware/pump_dac.cpp
+++ b/firmware/pump_dac.cpp
@@ -20,7 +20,7 @@ void SetPumpCurrentTarget(int32_t microampere)
     // 47 ohm resistor
     // 0.147 gain
     // effective resistance of 317 ohms
-    float volts = 0.000317308f * microampere;
+    float volts = 0.000321162f * microampere;
 
     // offset by 
     volts += 1.65f;