Property & Home · Repayments

Mortgage Calculator — What will it really cost?

Work out your repayments, the total interest, and what the loan costs you over its life.

What you enter

  • Loan amount
  • Interest rate
  • Loan term
  • Repayment frequency

How this is calculated

Repayments use the standard principal-and-interest amortisation formula: a fixed payment per period (monthly, fortnightly or weekly) such that the loan reaches zero exactly at the end of the term, with interest charged on the remaining balance each period. Total interest is everything you pay beyond the original loan amount. The rate is held constant for the whole term.

Common questions

Why is fortnightly cheaper than monthly?

Paying half the monthly amount every fortnight results in 26 half-payments — the equivalent of 13 monthly payments a year instead of 12 — plus interest accrues on a slightly lower average balance. The effect is real but modest; the "extra payment per year" is doing most of the work.

Will my actual repayment match this?

Your lender's figure should be very close for the same rate and term, but fees (annual package fees, offset account fees) and rounding differ. And your rate won't stay fixed for 30 years — the results show what a 1% rise does to the repayment.

What's not included?

Lender fees, Lenders Mortgage Insurance, offset accounts, redraw, interest-only periods, rate changes and refinancing. For offset and extra-repayment strategies, use the Mortgage Optimiser.

How does it rank?

Once you have your result, see how your number compares against your demographic with our full money rank — by age, sex, state and household composition.

Methodology & data

PRINCIPAL & INTEREST · INDICATIVE. Australian context, FY 2026–27 tax brackets by default (15% lowest marginal rate from 1 July 2026) with a financial-year selector on tax calculators. Calculations are indicative and based on simplified public models — not personal financial, tax or legal advice. See the full disclaimer.

Primary data sources

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