About the Mortgage Repayment Calculator
This works out the fixed repayment amount for a standard principal-and-interest home loan, at whatever frequency you pay — weekly, fortnightly or monthly — along with the total interest you'll pay over the life of the loan.
A common mix-up when comparing loans is treating a weekly or fortnightly figure as if it were just the monthly repayment split evenly. It isn't — a lender's real weekly cycle (52 payments a year) or fortnightly cycle (26 payments a year) is calculated directly from the loan terms, not derived by dividing the monthly amount by 4 or 2. This calculates the real repayment for whichever frequency you choose, so the number matches what a lender would actually charge.
How it works
It uses the standard loan amortisation formula, applied at your chosen repayment frequency: the interest rate and number of repayments are converted to match (e.g. fortnightly means 26 repayments a year), then solved for the fixed payment that pays off the loan exactly by the end of the term.
Assumptions and behaviour
- Assumes a fixed rate for the full term — real variable rates move over time.
- Models a standard principal-and-interest loan, not interest-only.
- Fortnightly and weekly repayments here are the loan's calculated cycle payment, not simply the monthly amount split evenly — matching how most Australian lenders actually charge interest.
Limitations
- Doesn't include fees, offset accounts, or extra repayments — for those, see the Mortgage Offset Calculator or Extra Repayment Mortgage Calculator.
- Rate changes over the loan's life aren't modelled.
Privacy
The calculation runs entirely in your browser. Nothing is uploaded or stored.
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