mortgagelens is an independent, ad-light mortgage calculator built to give home buyers fast, transparent math they can actually check. It is run by a small team of software engineers who got tired of slow, cluttered mortgage tools that hide their assumptions behind pop-ups and lead-generation forms.
Every number on this site comes from a small set of well-known financial formulas — the standard loan amortization formula, PITI (principal, interest, taxes, insurance), the 28/36 debt-to-income rule, and a refinance break-even calculation. We do not invent proprietary "scores." The exact formulas, assumptions, and sources are published on our methodology page so anyone can verify them.
The calculation engine is plain JavaScript that runs entirely in your browser — nothing you type is uploaded or stored. The math is covered by an automated test suite, so the formulas behave the same way every time. If a result looks wrong, you can trace it back to a documented formula rather than a black box.
mortgagelens provides educational estimates only. We are not a lender, broker, or financial advisor, and nothing here is personalized financial advice. Interest rates, insurance, taxes, and loan terms vary by borrower and location — always confirm exact figures with a licensed lender before making a decision. For unbiased, official guidance we point readers to the Consumer Financial Protection Bureau (CFPB) and the U.S. Department of Housing and Urban Development (HUD).