About AmortizeLocal

AmortizeLocal does one job: build the complete amortization schedule for a fixed-rate loan — with extra payments, biweekly mode and proper exports — entirely inside your browser.

It exists because of what a loan calculator asks you to disclose: how much you owe, at what rate, and what you’re planning to do about it. That’s a refinance lead, and much of the mortgage-calculator internet is built to harvest exactly that — the calculator is the bait; your phone number and loan details are the catch. The trade is rarely stated out loud, which is what’s wrong with it.

The fix is architectural, not cosmetic. This site is static: there is no upload endpoint, no processing queue, no account system, no email field. The schedule math is a few kilobytes of JavaScript executing on your own device; your entries persist only in your browser’s localStorage, and the Excel, CSV and PDF files are generated locally too. That’s why the calculator works offline, and why the privacy claim can be verified in your browser’s DevTools Network tab rather than taken on faith.

Principles

• Local only. Your balance, rate and payoff plans never leave your device. Not “encrypted in transit” — never transmitted.
• Documented math. Every formula, rounding rule and convention is on the methodology page, with a worked example you can reproduce by hand. No black box.
• Honest limits. Fixed-rate loans only; variable rates and income-driven student plans have no knowable schedule, and the pages say so instead of pretending.
• Free without a catch. No signup, no email wall, no “premium export”. Your device does the work, so serving you costs almost nothing.

Who makes this

AmortizeLocal is built and maintained by an independent developer as part of a small family of single-purpose, local-first browser tools. It may eventually show unobtrusive ads to cover its costs — if it does, they will sit outside the tool and will never see your numbers, because the no-upload architecture doesn’t change with the funding model.

Found a number that disagrees with your lender’s schedule, or a loan situation the calculator handles badly? Get in touch — corrections are the most valuable mail this site receives.