Maybe

=IF(OR(M2="",L2=""),"",IF(M2-L20,M2-L2,""))


--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)

"Cyrus" wrote in message
...
I need help with a formula. I'm creating a spreadsheet where data entry
would indicate the time a patient arrives and than leaves. I need a
formula
that calculates this, but displays nothing if no time is entered (for
example
down the worksheet).

=IF((M2-L2)=0,""),IF((M2-L2)0,"h:mm")

This is what I have...I keep getting value error.

i want the time to display if the time is greater than zero, but if less
than zero, display nothing.

Thanks,

Cyrus