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Amortization Calculator

Calculate the monthly payment on an amortising loan and the split between principal and total interest.

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What Amortization Calculator does

An amortising loan is repaid in equal instalments that cover interest first and principal second. Early payments are mostly interest; later ones are mostly principal. That is why paying off a loan early saves less than people expect near the end and a great deal at the start.

Enter the amount, rate and term to see the payment and what the loan costs in total.

  • Loan amount, term in years and annual rate
  • Monthly payment
  • Total interest over the life of the loan

How to use Amortization Calculator

  1. 1

    Enter the loan details

    Amount, annual interest rate and term in years.

  2. 2

    Read the payment and the total interest

    The total interest is the figure that shows what the term is really costing.

  3. 3

    Compare terms

    Try a shorter term to see the trade against the monthly payment.

Limits and known behaviour

  • A payment-by-payment schedule table is not produced; the calculator reports the monthly payment and the totals.
  • Monthly compounding and a fixed rate are assumed throughout.
  • Fees, insurance and escrow are not included.
  • Overpayments and irregular payments are not modelled.
  • Amounts are calculated and displayed in US dollars using US lending conventions. The arithmetic is currency-independent, so the results hold for another currency if you read the symbol as your own.
  • Figures are estimates for comparison and planning. They are not financial advice, not a quote, and not an offer of credit.

Privacy and data handling

Runs entirely in your browser

  • Every figure you enter stays in this page. What you type about a loan is not transmitted, logged or stored anywhere.
  • There is no account, no saved history and no autosave: reloading the page clears the form.

Site-wide data handling, including analytics and advertising, is described in the privacy policy.

Frequently asked questions

Why is so little of my early payment reducing the balance?

Because interest is charged on the outstanding balance, which is at its largest at the start. As the balance falls the interest portion falls with it and the principal portion grows, which is why the split shifts over the term.

Does overpaying early help more than overpaying later?

Considerably. An overpayment removes principal that would otherwise accrue interest for every remaining month, so the earlier it happens the more interest it avoids.