Calculate time intervals

2000-02-04    Time    0    83

If you need to calculate the difference between two time values within a certain limit (e.g. when calculating elapsed work time), the worksheet function below can be useful since it makes it simple to perform the time interval calculation.

Function TimeInterval(StartTime As Double, EndTime As Double, LowerLimit As Double, UpperLimit As Double) As Double
' returns EndTime-StartTime limited by LowerLimit and UpperLimit
TimeInterval = 0
If StartTime > EndTime Then Exit Function
If StartTime > UpperLimit Then Exit Function
If EndTime < LowerLimit Then Exit Function
If StartTime < LowerLimit Then StartTime = LowerLimit
If EndTime > UpperLimit Then EndTime = UpperLimit
TimeInterval = EndTime - StartTime
End Function
Example:
The examples below assumes that you have a start time in cell A1 and an end time in cell B1.

Return the elapsed time within 00:00 and 08:00 (0 = 00:00):
=TimeInterval(A1;B1;0;8/24)

Return the elapsed time within 08:00 and 16:00:
=TimeInterval(A1;B1;8/24;16/24)

Return the elapsed time within 16:00 and 24:00 (1 = 24:00):
=TimeInterval(A1;B1;16/24;1)