I've got start and end time fields and am trying to work out a way of seeing if another time field falls within the start / end duration ie start=9:00am, end=10am, LookupTime=9:32am is LookupTime inside or outside the interval?

thanks

How about:

StartTime ≤ LookupTime and LookupTime ≤ EndTime

Note that this assumes all times are within the same day - i.e. no midnight crossing.

geeez, easy when you know how, thanks ... and yep always will be on the same day

geeez, easy when you know how, thanks ... and yep always will be on the same day

It's easy enough to include start and end date fields so that the method will work when somebody works late and goes until 1:00 am.

the other thing I'm trying to do is see if there's an overlap between the start / end times on different records ie record1 - start=9am, end=10am ... record2 - start=9:55am, end=10:30am ... there's a 5 minute overlap.

not sure if I should be trying to do this with conditional formating to highlight the overlap, or via a portal showing the 2 obverlapping records

See if this helps:

http://fmforums.com/forum/topic/61691-please-help-very-simple-calendarappt-manager/page__p__291727#entry291727

not sure if I should be trying to do this with conditional formating to highlight the overlap, or via a portal showing the 2 obverlapping records

That's entirely up to you - you need the identifying relationship in any case.

that looks exactly like what I'm trying to do, thanks heaps

that worked fine, thanks again