Excel not calculating time when 18:00 used and total is one hour or less

I have an Excel sheet that's calculating the difference between two times. Its very simple calculation that does not go past midnight.

The formula I'm using is =INT((B1-A1)*24)

This seems to work for most of the calculations, but when I use it against a time from 17:00 to 18:00 it will not calculate the difference. If the time is 16:00 to 17:00 it returns 1, If I use 18:00 to 20:00 it will return an answer of two. The input is formatted as time [hh]:mm, the output is formatted as General.

Any help is greatly appreciated.

Hi,

A1 and B1 are times using 24 hour clock and format of [hh]:mm
So my problem is when I have 18:00 and try to take away 17:00, it returns a zero, if I Input 17:00 and take away 16:00 it works fine, something about 18:00 and a one hour gap is tripping it up.

Thanks for the interest.

Hi,

That returns 24:00 when taking 17:00 from 18:00 ? My apologies if I'm missing something, I am trying to get a return of one hour

No need to apologise, mental arithmetic should have helped me there. Many thanks for providing the answer.