Home Loan Repayment Calculator

How to use it

Start with the property price and subtract your deposit or available equity. That gives you the loan amount. For an investment purchase, most lenders want genuine equity of 20% to 35% depending on the security and the structure, so the loan is usually 65% to 80% of the price.

Pick a rate that matches the product. Prime investment lending sits around 6% to 8% per annum on an indicative basis. SMSF loans price higher, roughly 6.5% to 9%, reflecting the limited-recourse structure. Bridging and private finance are short-term money and run higher again. The product pages linked below carry the indicative range for each type.

Set the term, then read the repayment. Now switch the frequency from monthly to fortnightly and watch what happens. Paying fortnightly usually means you make the equivalent of one extra monthly payment a year, which shortens the loan and cuts total interest. Then change one input at a time. A half-percent rate rise on a $700,000 loan over 30 years adds real money to the monthly figure. Seeing that swing is the whole point. It tells you how much headroom your budget needs before rates do something you cannot control.

What actually affects your repayment

Three numbers drive the repayment, and the term is the one people underrate.

The interest rate matters most over a long loan, because interest compounds across hundreds of payments. The loan amount is the obvious lever. The term is the quiet one. Stretching a loan from 25 to 30 years lowers the monthly repayment but lifts the total interest, sometimes by tens of thousands of dollars. A shorter term costs more each month and far less overall. Extra repayments work the same way in reverse: even a small amount above the minimum, paid consistently, can take years off the loan.

What the calculator leaves out matters just as much. It excludes the establishment or application fee, the valuation fee, the lender’s legal costs, the line fee on construction and development facilities, and Lenders Mortgage Insurance, which can apply on standard investment lending above 80% LVR. It also assumes one rate for the whole term. If you fix for two years and then revert to a variable rate, the real repayment changes when the fixed period ends. Every one of these costs is disclosed in writing, up front, before you commit.

The Australian context

A few terms matter here. Lenders assess your borrowing against an LVR, the Loan-to-Value Ratio, which is the loan as a percentage of the property’s value. They also apply a serviceability buffer, testing whether you could still meet repayments at a rate two to three percent above the actual rate. Investor lending attracts a tighter buffer than owner-occupier lending. So the repayment a calculator says you can afford and the amount a lender will actually advance are often different numbers.

Settlement is the AU term for completion, the day funds change hands. For an SMSF purchase under a Limited Recourse Borrowing Arrangement, the fund acquires a single property held in a separate bare trust, and the LVR caps sit lower, around 70% for residential and 65% for commercial SMSF security. The repayment maths is identical. The structure and the lending rules are not. SMSF borrowing needs independent financial and tax advice before you proceed, and Windsor does not give that advice.

This is where a repayment calculator reaches its limit. It cannot read your security, your income evidence, or your exit plan. A broker can.

Why the repayment figure is only step one

The number on the screen is generic. It does not know that your income is self-employed and lumpy, that the property is a regional or non-standard security, or that you need to settle in three weeks. It cannot tell you which lender on a panel will say yes to your structure, or at what rate. Go direct to one bank and you get that one bank’s answer. A broker takes a single enquiry to banks, non-bank lenders, and private credit funds at once, then packages the file so the right lender sees a clean case the first time.

That is the gap between an estimate and a real assessment. The calculator gives you the shape of the repayment. We find the lender who will fund it, and structure the loan so the repayment works for the deal.