We just sent out excel sheets that would automatically mark-up our price sheets based on 10-50% or whatever they typed into the input box. However the customers need a an input box that they can type in and give them a predetermined margin (20%, etc.)

Anybody knows how to figure a gross margin (1- cost divided by price), but what's the backwards equation to calculate a predetermined margin for a spreadsheet. I know it's gotta be simple, but frankly I've never used it...or is it a function I'm not aware of.

This was a stupidly huge error.