It would help if you told us what was in M7, R7 and Q7.

To check for credits use:
=if(SellingPrice<0,0,(ListPrice-SellingPrice)/ListPrice)

Regards,
Fred

"Wanna Learn" wrote in message
...
Hello
In excel 2003 I have the following columns
Price Selling price total sale units sold
2914.00 2409.00 4818.00 2
This is my formula to give the % discount =-1*(Q7/R7-M7)/M7
answer is 17.33% discount
However
There are times that the total sales is a credit(e.g. product was
returned)
How do I correct the formula so that when the total sales is a credit I
get
blank cell