There is no easy userfriendly way to enter negative time. This will work:
-"04:00"
and this
=-TIME(4,0,)

Formatting as -h:mm will just display a - in front of the positive number.
Formatting does NOT change value, so the cell will still contain a positive
number.

I'd use a small macro that change sign in the selected cell(s):

Sub ChangeSign()
Dim Cel As Range
On Error Resume Next
For Each Cel In Intersect(Selection, ActiveSheet.UsedRange)
If Cel.HasFormula = False Then Cel.Value = -Cel.Value
Next
End Sub

HTH. Best wishes Harald

"B. Baumgartner"
skrev i melding
news:B.Baumgartner.1rgxia_1120183505.8262@excelfor um-nospam.com...

I have a cell into which I would like to input a time value, either
negative or positive from which other cells will perform calculations.

When I enter the time as a positive value it works fine, however if I
attempt to put the value in as a negative, i get a popup that says "The
formula you typed contains an error. If you are not trying to enter a
formula avoid using the - sign."

If I format the cell as -h:mm, it has no problem processing the value
entered, however I cannot enter a positive value. This same error
occurs no matter how the cell is format, from General, to Number, to
Time, to Custom Time.

I have the 1904 date system enabled if that helps with the problem
solving.


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B. Baumgartner
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