← Blogby Marcell Almeida

How to calculate monthly mortgage payments

Enter loan amount, rate, and term — see monthly payment, total interest, and a year-one amortization schedule instantly.

Before you sign, you need to know the monthly payment and how much interest you will pay over the life of the loan. The Mortgage Calculator uses the standard amortization formula and shows the first 12 months of your schedule — no spreadsheet required.

Try it — enter loan amount, rate, and term

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How it works

  1. Loan amount — principal borrowed after your down payment.
  2. Interest rate — annual percentage rate (APR) from your lender.
  3. Term — loan length in years (30, 20, 15 are common).

The payment formula

Monthly payment = P × [r(1+r)n] / [(1+r)n − 1], where P is principal, r is monthly rate (annual ÷ 12), and n is total months. Early payments are mostly interest; later payments shift toward principal.

What this does not include

Property tax, homeowners insurance, PMI, and HOA fees are not in this calculator. Add those separately for total housing cost.

Also see the Loan Calculator for personal or auto loans measured in months.

The How to calculate monthly mortgage payments is free, runs locally, and never sends your data to a server. More finance calculators at maratool.com.