Assuming your numbers are in cells A1 B1 and C1 then put this formula in cell
D1:

=IF(A1<B1,(ROUNDUP((B1-A1)/C1,0))*C1,0)

Tom

"Jackie Morin" wrote:

How do I have a cell look at another cell and make a calculation. For example:

A B C
(197) 3500 500

If column A is less than B then have the calculation of the amount of (C) it
would take to bring it to positive standing. The answer should be 4000. That
is (8) lots of 500 to make the amount 3803. That is C times (8) minus 197. If
(A) was 3501 then I would have a return value of 0. I would not need to
replenish.