You don't need a macro put this formula in the cell instead.

=IF(OR(C5="",B5=""),"",C5-B5)

Mike

"bumblebug787" wrote:

How do I write a macro to tell a cell not to perform the calculation in it if
one of the cells in the calculation is empty? In other words, "Don't do
C5-B5 if C5 is null"