I need to check two cells for blanks and report a zero if the cell is blank. If EITHER of the cells are not blank, I need to make a simple computation. I can write the formula for one cell or for the other, but I don't know how to COMBINE the two "IF" statements. In Lotus, I seem to recall a function called "OR_IF", but can't seem to find a way to do it in Excel. Here's the two formulae I need to combine:

=if(a1="",0,c1-d1) OR =if(b1="",0,c1-d1)

If EITHER a1 or b1 is blank, i want to subtract d1 from c1. Can anyone help me with the "OR" function with two embedded "IF" statements?

Thx,
-Willcy-