Percenatges in excel

Hello, could someone help? I have an excel sheet where I want to be able to add a % as a GP to a cell that looks at a buying cost and adds the percentage in another cell. IE £100 would become £125 with 20% GP. So £100 in A1 20% in B1 and then £125 would appear in C1. C1 would have the formula in. The % would need to be various different ones according to what was needed. Can anyone help me?

How does £100 + 20% equate to £125 rather than £100?

Its when you talk about gross profit rather than mark up. £120 is 20% mark up rather then GP. £100 + 20% GP is £125. Any ideas how I can achieve this result? I used to have a formula which worked in my last job so I know it can be done,

Okay, use

=A1/(1-B1)

Bob,

Thanks for that very much, I've tried for a long time to work that out, new t was a simple thing, but.......?