I need to identify where the time between end of one visit and start of another is < 5 mins and be able to amend that figure from time to time. I have tried to use IF formula but it does not like 00:05 in formula (ie IF((C3--D2< 0:05)1," "). Tried using the number excel creates for time but this does not work either, presumably because of so many decimal places. Can anyone suggest anything else