Excel can solve for unknown variables, either for a single cell with Goal Seek or multiple cells with Solver.

Solve Equations in Excel using Solver Add-in Solver Add-in is a powerful and useful tool of Excel which performs calculations to give the optimal solutions meeting the specified criteria.

Stop guessing! Susan Harkins shows you how to use Excel's Goal Seek what-if analysis tool to achieve your goals.

"Chief Excel Officer" Chandoo runs down how to use Excel's Goal Seek feature to create a kind of retirement target advisor. You'll fill out a spreadsheet with the financial status you seek to ...