subtracting time going backwards past midnight?

[Billman]

I am trying to track time going backwards. In other words I am backing into a
start time. I am having problems when I cross midnight going backwards.

 

[T. Valko]

Try this:

A1 = 7:00 PM
B1 = 3:00 AM

=MOD(B1-A1,1)

Format as h:mm = 8:00

Or, if you want the result in decimal format:

=MOD(B1-A1,1)*24

Format as GENERAL or NUMBER = 8

 

[Tyro]

You will have a problem there. Excel maintains times as fractions of 24
hours. To keep accurate time, you must also take date into account.
as Excel maintains time and dates as date.time That is to say, the date is
maintained as a whole number and the time as a fraction.

Tyro

 

[Teethless mama]

=B1-A1+(A1>B1)

Fomat cell as h:mm