diff --git a/src/shared/drivers/adc/InternalADC.cpp b/src/shared/drivers/adc/InternalADC.cpp
index b4c63d4bb3c2e7717a9814c3d61057ae812c2df9..525c56e10a1a35c15c2606c6a2eec11eaefee154 100644
--- a/src/shared/drivers/adc/InternalADC.cpp
+++ b/src/shared/drivers/adc/InternalADC.cpp
@@ -299,7 +299,7 @@ void InternalADC::loadCalibrationValues()
     calPt2Voltage = static_cast<float>(*CAL_PT2_VALUE);
     calPt2Voltage *= CAL_V_DDA / ADC_RESOLUTION;
 
-    calSlope = calPt1Voltage - calPt2Voltage;
+    calSlope = calPt2Voltage - calPt1Voltage;
     calSlope /= CAL_PT2_TEMP - CAL_PT1_TEMP;
 }
 #endif