About MortgageMath
MortgageMath is the borrower's side of the biggest loan most people ever take: the full monthly payment, what extra payments buy, what you can afford, and when refinancing pays.
MortgageMath exists because the quoted "payment" is never the payment — taxes, insurance, and PMI ride along, and the amortization schedule hides most of the cost in plain sight. These calculators surface all four lines and the interest total.
Every calculator on MortgageMath shows its formula and its assumptions on the page, so you can check the math, reproduce it in a spreadsheet, or argue with it. Inputs are processed entirely in your browser — nothing is sent to a server, and there are no accounts.
MortgageMath is an independent, ad-supported project. We are not affiliated with any lender, brand, agency, or the sources we cite (CFPB and IRS public guidance). If a number looks wrong, the contact page reaches a human who fixes it.
What makes MortgageMath different
- Your numbers never leave your browser. Every calculator on MortgageMath runs entirely on your device. We never see, store, or transmit the figures you enter — there are no accounts and no server-side processing of your inputs.
- Published methodology. Each calculator page explains the exact formula it uses and the assumptions behind it, so you can check our work or reproduce it in a spreadsheet.
- Free, forever, without a paywall. MortgageMath is supported by advertising. There is no premium tier, no email gate, and no upsell.
Independence
MortgageMath is an independent educational project. We are not affiliated with, endorsed by, or acting on behalf of any government agency, lender, insurer, or the organizations whose formulas and public data we reference (such as CFPB and IRS public guidance). All trademarks and referenced standards belong to their respective owners.
Questions, corrections, or suggestions are genuinely welcome — get in touch.