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Mortgage Affordability Calculator

Estimate how much you could borrow for a home based on your income, expenses, debts and deposit.

  1. Enter your numbers
  2. Results update as you type
  3. Copy the answer or share the link
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About the Mortgage Affordability Calculator

Get a realistic first estimate of how much a lender might let you borrow and what price range to look in, based on income, living costs, existing debts and your deposit.

How does the Mortgage Affordability Calculator work?

Your after-tax income less living expenses and existing repayments gives a monthly surplus. Lenders test whether you could still afford repayments if rates rose — the serviceability buffer — so the loan is sized for the surplus at the higher test rate.

The estimate keeps a margin rather than committing every spare dollar, and also shows your debt-to-income ratio, which many lenders cap.

Mortgage Affordability Calculator formula

max loan = PMT × (1 − (1 + r)^−n) ÷ r

PMT is the repayment you can afford and r the monthly test rate (actual rate + buffer).

Guides

Frequently asked questions

Why is my bank’s figure different?

Lenders use their own living-expense benchmarks, count some income (bonuses, rent) at a discount, and apply credit card limits rather than balances. Treat this as a starting point.

What is a serviceability buffer?

An extra margin, often 3 percentage points, added to the interest rate when assessing whether you can afford a loan, so a future rate rise doesn’t put you in stress.

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