PayDownMath builds free calculators for homeowners deciding what to do with extra money — a bonus, an inheritance, the proceeds from a house that just sold.
Most mortgage calculators are published by lenders and servicers, and they tend to show the option that suits the publisher. Ask a recast calculator whether to recast, and it will show you a lower payment. It will not show you what happens if you send the same money and keep paying your current amount instead — which frequently saves more.
Every calculator here shows the alternatives alongside the option you searched for, including the option of doing nothing.
Everything runs on standard amortization math in your browser. Nothing you type is transmitted to a server or stored, unless you choose to send it with a request for your breakdown. The formulas are the same ones your servicer uses: a fixed payment applied monthly against a declining balance at your stated rate.
What the calculators cannot know is your servicer's specific rules — minimum amounts, fees, eligibility. Those vary, and the pages here say so wherever it matters.
PayDownMath is built and maintained by Behbud Ramazan, an independent developer whose background is in financial software rather than in lending. The site is not affiliated with, sponsored by, or endorsed by any bank, mortgage lender, loan servicer, or government agency.
That independence is the whole point. There is no product being sold here and no loan being placed, so the calculators are free to show the option that costs you least — including when that option is doing nothing at all.
PayDownMath is free to use. The site is supported by display advertising and, where relevant, referral relationships with lenders. Advertising never determines what a calculator recommends — the math produces the same result regardless of who is advertising on the page.
PayDownMath is not a lender, mortgage broker, loan originator, credit counselor, or licensed financial adviser, and is not licensed to provide financial, legal, or tax advice in any jurisdiction. Nothing on this site constitutes financial advice or a recommendation, and using it does not create an advisory, fiduciary, or professional relationship of any kind.
The calculators produce estimates from the numbers you enter, using standard amortization formulas. They cannot account for your servicer’s specific rules, your full financial position, or your tax situation. No warranty is given as to accuracy, completeness, or suitability for your circumstances, and no liability is accepted for decisions made on the basis of these figures.
Before acting on anything here, confirm the specifics with your loan servicer and, where the amounts are significant, with a licensed professional.
If something here is wrong, tell me. See the contact page. Corrections are made promptly and the review date on the page is updated.