About Clear Money Math

Clear Money Math builds free, fast calculators for the money decisions people actually face: when you can stop saving for retirement, which debt to pay off first, whether a mortgage recast is worth it. Every tool shows its formula, a worked example and its sources, so you never have to take a number on faith.

Who's behind Clear Money Math

Patrick Legallais is the founder and editor of Clear Money Math. He created the site because most online money calculators hide their assumptions, bury the answer under ads, or quietly steer you toward a product. He reviews every calculator, article and correction before it is published.

Patrick Legallais is not a licensed financial adviser, and Clear Money Math does not give personalized advice. The site's job is to make the math behind common decisions clear, so you can make your own choices or have a better-informed conversation with a professional.

How we build our calculators

• The math is on the page. Every calculator explains its formula and walks through a worked example.
• Tested against known values. Each calculation is covered by automated tests against textbook results before anything is published.
• Sourced. Facts and rules of thumb are checked against primary sources such as the CFPB, the Federal Reserve and the IRS, and listed on each page.
• Reviewed and dated. Each page shows when it was last reviewed. If you spot an error, tell us and we'll fix it.
• Private by design. Calculations run entirely in your browser. The numbers you type are never sent to our servers.

Read the full methodology.

How the site is funded

Clear Money Math is free to use and supported by advertising. Ads never influence how a calculator works or what it shows.

Questions or corrections: hello@clearmoneymath.com