That formula works OK for me. Another way to write it would be:

=MAX(AT1-AV1,0)

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Biff
Microsoft Excel MVP


"LCCHELP" wrote in message
...
I have input the following if function

if(at1av1,at1-av1,0) however if the number in av1 is greater than at1 it
returns a negative number, rather than returning 0.

can someone enlighten me as to what I have missed.

thanks