time equation in form

[WCR]

I am trying to subtract two time period fields in my form so that the correct total amount of time will be placed into the total hours missed field.

Example: current Control Source entry is = End Time - Start Time

End time field entry 21:00 , Start time field 20:30 , Total Missed field 30
this works OK for any time before midnight but when I try to use the following
time - End Time 2:15 and Start Time 00:00 the answer comes out wrong in the Total missed time field . It should be 2.15 hours but it comes out a much larger number. What change do I need to make in my Control Source to compensate for going past midnight. Any suggestions? Thanks

[pbaldy]

The most reliable method would be to store the date with the time. You can also use things like this:

http://www.mvps.org/access/datetime/date0004.htm

[WCR]

I used the format([start time]-1-[end time],"Short Time" and that worked great in my form. But when I went to my Table data sheet the calculation wasn't recording correctly. Any suggestions. Thanks much.