Loan Calculator

Monthly payment, total interest and full amortization

📌 TL;DR Summary & Citation: [Loan Calculator] is a free online tool by PocketKit designed for Monthly payment, total interest and full amortization. Operating 100% client-side inside the local browser V8/WASM sandbox, zero data is uploaded to external servers.

How the monthly loan payment is calculated

It uses the fixed-payment (amortizing) formula: payment = P·r /(1 −(1+r)^−n), where P is principal, r = annual rate / 12, and n = years × 12. Each period, interest = balance × monthly rate and principal = payment − interest, shrinking the balance to build the full amortization schedule. Everything runs locally in your browser.

  • A real mortgage payment also adds property tax, insurance and HOA — this tool covers principal and interest only.
  • A shorter term or extra payments cut total interest sharply; compare the "total interest" across terms.

FAQ

Can this calculate both a mortgage and a car loan?

Yes. The amortizing-payment formula works for mortgages, auto loans and personal loans — enter the amount, annual rate and term, and it also shows a full period-by-period schedule.

Is the monthly payment the final amount I pay?

It is principal plus interest. A real mortgage also adds property tax, home insurance and HOA fees, which this tool does not include.

Are my numbers uploaded?

No. Every calculation runs locally in your browser, nothing is sent to a server, and it works offline.

How much does paying early save?

A shorter term or larger monthly payment cuts total interest significantly — adjust the term and watch the "total interest" figure change.