Calculating time data types

[anlimah]

how do I employ the diffdate function to add time data types. ex start time 9:00 end time 10:00, how to assign to field entitled length. want field to update automatically to read 1:00? not sure how to use function. please help, I've been struggling with this for a week. Many thanks.

[pbaldy]

You can simply subtract:

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

DateDiff() would calculate a number of minutes/hours/etc.