Fixed vs Variable Mortgage Calculator
Compare a fixed-rate home loan against variable rate scenarios in Australia to see which could cost less under falling, flat or rising interest rates.
Your results
Calculation breakdown
- Break-even rate
- The flat variable rate that would produce the same total cost as the fixed loan over the comparison window
Assumptions
- We cannot and do not predict future interest rates — the three scenarios are illustrative only, and you can edit each one.
- The fixed loan reverts to the entered revert rate once the fixed period ends.
- Extra repayments are applied to both the fixed and variable comparisons for a fair comparison.
How this calculator works
Deciding between a fixed and variable home loan rate means weighing the certainty of a locked-in repayment against the possibility that variable rates could end up lower — or higher — over the same period. This calculator compares your fixed rate loan, which reverts to a revert rate you specify once the fixed period ends, against three illustrative variable rate scenarios: falling, flat and rising, each driven by a rate-of-change figure you can edit. It totals the cost of each option over your chosen comparison window and calculates a break-even average variable rate — the flat variable rate that would produce the same total cost as the fixed loan — so you can judge whether you think average variable rates over the period are likely to sit above or below that number. No calculator can predict future interest rate movements, so treat the three scenarios as a way to stress-test your decision rather than a forecast, and remember that fixing usually comes with less flexibility, such as limits on extra repayments and early exit fees.
Frequently asked questions
What is the 'break-even average variable rate'?
It's the flat variable interest rate that would make the variable loan cost the same in total as the fixed loan over your comparison window. If you expect the average variable rate to stay below this figure, variable would likely cost less.
Can this calculator predict whether rates will rise or fall?
No. The falling, flat and rising scenarios are illustrative only and fully editable — this tool helps you compare outcomes under different assumptions, not forecast what the Reserve Bank or lenders will actually do.
What happens to my fixed loan after the fixed period ends?
It reverts to the revert rate you enter, which is often higher than the initial fixed rate. Many borrowers refinance or renegotiate before the fixed period ends to avoid moving onto an uncompetitive revert rate.
Results are estimates only and are not financial, tax, legal or credit advice.