diff --git a/TimingCore.h b/TimingCore.h
index 14f8ece..3211f10 100644
--- a/TimingCore.h
+++ b/TimingCore.h
@@ -63,6 +63,18 @@ inline long SecondsPassed( timeval StartTime ) {
 };
 //---------------------------------------------------------------------------
 
+// Milli-seconds difference between two times
+inline long TimeDiff( timeval StartTime, timeval EndTime ) {
+    long    Duration;
+
+    Duration = (EndTime.tv_sec - StartTime.tv_sec) * (time_t)1000 +
+               (EndTime.tv_usec - StartTime.tv_usec) / (time_t)1000;
+    if (Duration < 0)
+        Duration = LONG_MAX;
+    return Duration;
+};
+//---------------------------------------------------------------------------
+
 // Time remaining from Start time to given time out
 inline long TimeLeft( timeval StartTime, long MilliSeconds ) {
     return (MilliSeconds - TimePassed(StartTime));