- Enter the loan amount (the price minus your down payment), the annual interest rate and the term in years.
- The calculator uses the standard amortisation formula — the same one lenders use — to find the fixed monthly payment.
- Add an optional extra monthly payment to see how many months and how much interest you save by overpaying.
- Works with any currency — just think in dollars, pounds or euros; the maths is identical.
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Mortgage Calculator — Monthly Payment and Total Interest
See exactly what a home loan costs. Enter the amount, interest rate and term to get your monthly repayment and the total interest you'll pay over the life of the mortgage — plus see how much an extra monthly payment saves.
How the mortgage calculator works
Frequently asked questions
How is a monthly mortgage payment calculated?
Lenders use an amortisation formula: each payment covers that month's interest first, and the rest reduces the balance. Over time the interest share shrinks and the principal share grows, keeping the payment fixed.
How much do extra payments save?
Because extra payments cut the principal directly, savings compound. On a 30-year $300,000 mortgage at 4.5%, paying an extra $100 a month can save tens of thousands in interest and clear the loan years earlier.
Does this include taxes and insurance?
No — it shows principal and interest only. Your full monthly housing cost (PITI) also includes property tax, home insurance and possibly HOA fees, which vary by location.
What mortgage term is best?
Shorter terms mean higher monthly payments but far less total interest; longer terms lower the monthly cost but increase the lifetime interest. Use the extra-payment field to find a middle path.
Estimates are for guidance only and are based on published 2025/2026 rates. Always confirm with a qualified professional for financial decisions.