How to calculate time difference from a text value

Question

I'm making a customised roster worksheet to schedule employees' shifts. There are days when employees have to work on split shifts. I was surfing the web and found this idea in the following link quite impressive.
https://www.findmyshift.com/au/free-excel-roster-template

This has vba code on it (which is locked ofcoz) which returns the cell value "8am-2pm" to "6" (means calculate the time difference given in text format).
For split shifts, cell value "8am-2pm/4pm-9pm" will return "11".

Can someone please be able to provide me a code to achieve similar results.
Thanks in advance.

Answer 1

Here's your function. It can handle any number of shifts, with hours or hours and minutes and spanning across midnight like 8:30pm-2:45am :

Public Function TimeDifference(s As String) As Variant
    On Error GoTo Handler
    Dim shifts() As String
    Dim result As Double
    Dim hours() As String
    Dim duration As Double
    result = 0
    shifts = Split(s, "/")
    For Each shift In shifts
        hours = Split(shift, "-")
        duration = TimeValue(hours(1)) - TimeValue(hours(0))
        If duration < 0 Then
            duration = duration + 1
        End If
        result = result + duration * 24
    Next shift
    TimeDifference = result
    Exit Function
Handler:
    TimeDifference = CVErr(xlErrValue)
End Function