Use

=MOD(B1-A1,1)

--

HTH

Bob

"Ian R" wrote in message
m...
Hi

I'm using Excel 2003.

I'm trying to calculate the total hours (C1) by subtracting end time
(B1) from start time (A1)

I have formatted the cells for time.

I'm currently using B1-A1 which works OK until the end time goes past
midnight.

e.g start 19:50 end 00:20 should = 4:30 except i just get an endless
series of #######

Thanks for your time.

Ian