Zerdly

Mortgage Repayment Calculator

Estimate mortgage repayments and total interest on your home loan based on rate and term, free right in your browser.

100% FreeRuns in your browserIntermediate
How to use this calculator

Enter Values

Minimum 0

Minimum 0

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Enter your values and press Calculate to see results.

Before you rely on this: Estimates only — not financial, tax or legal advice. Confirm current rates, fees and rules before relying on these figures.

How to use this calculator

  1. Enter the loan amount, the annual interest rate and the loan term.
  2. Press Calculate for the monthly repayment and total interest.

How it works

A mortgage is repaid in equal instalments using the amortised formula M = P·i ÷ (1 − (1 + i)^−n), where i is the monthly interest rate and n the total number of monthly payments.

Worked example

$500,000 at 6% over 30 years. That's roughly $3,000 a month — change the inputs to match your loan.

Common mistakes

  • Entering the property price instead of the loan amount — use what you're actually borrowing.
  • Underestimating how much a small rate rise adds over a 25–30 year term.
  • Forgetting ongoing costs (council rates, insurance, strata) that sit outside the loan repayment.

Frequently asked questions

How are mortgage repayments calculated?

From the loan amount, interest rate and term using the amortisation formula, so each repayment covers interest plus a growing slice of principal. The tool shows the regular payment and total interest.

Does a shorter term save money?

Yes — a shorter term means higher repayments but far less total interest, since you owe the balance for less time. The tool lets you compare terms.

Fixed or variable?

This assumes a fixed rate for the whole term. A variable rate changes your repayment when rates move.

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Cite this tool

Zerdly. (2026). Mortgage Repayment Calculator. Retrieved from https://www.zerdly.com/tools/mortgage-repayment-calculator/

Tip: Enter any known values to calculate the remaining results.

All calculations run in your browser. Your inputs are never saved or transmitted.