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Mortgage Amortization Calculator

See how a fixed mortgage shifts from mostly interest to mostly principal over time.

Mortgage Amortization Calculator estimate

Enter values, then calculate.

How the estimate works

Each month applies interest to the outstanding balance, then subtracts the scheduled payment and any extra principal.

Worked example

Example: on a $400,000, 30-year loan at 6.5%, the first payment is mostly interest. The annual table shows how principal reduction accelerates later in the term.

Important limitation

Taxes, insurance, adjustable rates, escrow, and payment timing are not included. Results are estimates only and are not financial, lending, legal, tax, or investment advice.

Assumptions and review

Formula review: July 29, 2026. This tool uses only the editable values shown above and does not pull live rates, prices, balances, or account data.

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Frequently asked questions

How does the mortgage amortization calculator work?

Each month applies interest to the outstanding balance, then subtracts the scheduled payment and any extra principal.

Is this mortgage amortization calculator exact?

No. It is a planning estimate based on the values you enter. Actual rates, fees, timing, taxes, and provider rules can change the result.

Can I change the assumptions?

Yes. Every displayed input is editable so you can compare scenarios instead of relying on a hidden default.