Enter an amount, a rate and a term, and this works out the regular repayment and what the loan costs in total.
The total is the number worth looking at. A repayment tells you whether you can afford the month; the total interest tells you what the loan actually costs, and on a thirty-year term it is frequently more than half the amount borrowed again.
Works out the regular repayment on a home loan, and what it adds up to in interest over the full term.
Loan amount
What you borrow, not what the property costs. If you are putting a deposit down, subtract it first — and remember that lenders mortgage insurance, when it applies, is usually added to the loan rather than paid separately.
Interest rate
The annual rate as a percentage. Use the rate you will actually be charged rather than an advertised headline: the two differ when a discount is conditional on a package fee, and a comparison rate is a different number again.
Term
How long the loan runs, in years. Thirty is the Australian default and it is a choice, not a rule — the term drives the total interest far more strongly than most borrowers expect.
Repayment frequency
Monthly, fortnightly or weekly. This is the frequency the repayment is calculated at, which is not the same as taking a monthly repayment and paying half of it every fortnight — see the fortnightly repayment calculator for why that distinction matters.
The headline figure is the repayment for the period you chose. It is the same every period: this is a principal-and-interest loan at a fixed rate, so the payment does not change even though its composition does.
Total interest is what you pay the lender for the privilege. Early in the loan most of each repayment goes to interest and very little to the balance; the crossover point on a typical thirty-year Australian loan arrives somewhere around year eighteen. That is why an extra repayment made in year two is worth so much more than the same amount in year twenty.
Total cost is the amount borrowed plus the interest. It is the number to carry into a conversation about whether to borrow more, extend the term, or wait.
Every figure below is computed by the same calculator on this page, from the inputs described. Nothing here is typed in by hand, so an example cannot disagree with the tool.
Look at the total interest against the amount borrowed. Over a thirty-year term at this rate the interest exceeds the principal — the loan costs more than twice what was borrowed.
Five years shorter. The repayment rises by a few hundred dollars a month and the total interest falls by a figure most borrowers find startling. Term is the lever people negotiate least and it moves the total most.
The standard amortisation formula. The annual rate is divided by the number of periods in a year to give a periodic rate, and the repayment is the amount that reduces the balance to exactly zero over the number of periods in the term.
Interest is charged on the outstanding balance each period before the repayment is applied, which is why the split between interest and principal moves over the life of the loan without the repayment changing.
Calculations are performed at full precision and rounded only for display. A schedule computed by rounding each period to the cent and carrying the rounded figure forward accumulates error across three hundred and sixty periods; this one does not.
The rate does not change
A variable rate will. The result is the loan as it would run if today’s rate held for the whole term, which is a useful baseline and not a forecast.
Nothing is paid early
No extra repayments, no lump sums, no offset balance. Each of those has its own calculator, because each changes the answer in a different way.
Fees are excluded
Establishment fees, ongoing account fees and package fees are not in the repayment. They are real costs and they belong in a comparison; they are simply not part of what the amortisation formula computes.
It is not a lending decision
A lender assesses serviceability against its own buffer rate, your expenses, your other commitments and its credit policy. A repayment you can afford on this page is not an approval and does not predict one.
Fixed-rate periods are not modelled
A loan fixed for three years and variable after is two rate environments. Run it twice — once at the fixed rate, once at the expected revert rate — rather than treating either as the whole picture.
Interest-only periods are elsewhere
If your loan does not repay principal for the first few years, this understates both the later repayment and the total interest. The interest-only calculator handles that shape.
Shows how paying more than the minimum each period shortens a home loan and cuts the interest paid.
Estimates what holding a balance in a full offset account saves in interest, and how much sooner the loan closes if repayments stay the same.
Compares two home loans on repayment, total interest and total cost, so the difference between them is explicit.
Works out the loan-to-value ratio: how much is borrowed as a percentage of what the property is worth.
Separates the two things people mean by "paying fortnightly": genuinely repaying every fortnight, and paying half a monthly repayment every fortnight — which is thirteen monthly repayments a year.
This calculator can be embedded on a business website, branded to match it, with a call to action that sends the enquiry to that business rather than collecting anything here.