You can solve the problem best by including the date as well as the time in
the field. If you do that:
DateDiff("n", [Time In], [Time Out])
will give you the correct number of minutes, even if it spans midnight.

If that is not suitable and you are absolutely certain that there will ever
be a graveyard shift of 12 hours or more duration, you could use:
Minutes: DateDiff("n", [Time In],
IIf([Time In] [Time Out], CDate(1+[Time Out]), [Time Out]))

These calculations give you the duration in minutes, so you can perform
numerical function such as sum, average, or calculate wages. If you wish to
display the result on a report in minutes and hours, the Control Source for
the text box would be:
=[Minutes] \ 60 & Format([Minutes] Mod 60, "\:00")

--
Allen Browne - Microsoft MVP. Perth, Western Australia.
Tips for Access users - http://allenbrowne.com/tips.html
Reply to group, rather than allenbrowne at mvps dot org.

"ELL" wrote in message
...
I am trying to design a time sheet to calculate automatically the time
entered for all shifts. This includes graveyard. Unfortunately I cannot
seem to put together the right formula to calculate all time sets. Can
anyone help me?

Example:
Time In Time Out I get Time Should be
18:00 03:00 15:00 9:00

Thanks for any help you can give.
--
ELL