diff --git a/AutoPID.cpp b/AutoPID.cpp
index 64a5f49..963dcd4 100644
--- a/AutoPID.cpp
+++ b/AutoPID.cpp
@@ -59,7 +59,7 @@ void AutoPID::run() {
       double _error = *_setpoint - *_input;
       _integral += (_error + _previousError) / 2 * _dT / 1000.0;   //Riemann sum integral
       //_integral = constrain(_integral, _outputMin/_Ki, _outputMax/_Ki);
-      double _dError = (_error - _previousError) / _dT / 1000.0;   //derivative
+      double _dError = (_error - _previousError) / (_dT / 1000.0);   //derivative
       _previousError = _error;
       double PID = (_Kp * _error) + (_Ki * _integral) + (_Kd * _dError);
       //*_output = _outputMin + (constrain(PID, 0, 1) * (_outputMax - _outputMin));