Borrowing capacity calculator
Put in your income, your repayments, your spending and the interest rate you've been quoted. The calculator works out what's left after tax each month, then the biggest loan that amount could repay if the rate were 3 percentage points higher, which is the minimum test APRA expects banks to use. Every step is shown, so you can see why the figure is what it is. A lender counts your income and costs its own way, so its figure is usually lower.
Work out what your figures could borrow
Six figures, worked out in your browser. Nothing is sent anywhere and nothing is stored.
What this assumes
- Income tax and the 2% Medicare levy come off each earner's income separately, at 2026–27 resident rates. Tax offsets, HECS-HELP and the Medicare levy surcharge aren't counted.
- Your loan and card repayments and your spending come off what's left, as you typed them.
- What remains is tested at your rate plus 3 percentage points, over the term you chose.
- Lenders count a repayment on each card's full limit, not what you owe. Put that in, not what you usually pay, or the figure will run high.
- Overtime, bonuses, rent, dependants and a lender's own living-cost benchmark aren't modelled, because each lender treats them differently.
Buffer: APRA, at least 3 percentage points, re-read 29 September 2026. Tax: 2026–27 resident rates.
An estimate on your own figures, worked out in your browser. It isn't an assessment, an approval or an offer.
How the calculator gets its figure
Tax comes off first. Each earner's income is taxed separately, with the Medicare levy, to give what you take home each month.
Then your repayments and spending. What you pay on loans and cards, and everything else you spend, come off what you take home.
What's left is what a loan repayment could use. Nothing is held back for savings or surprises, which is why this is the top of the range, not the middle.
The rate goes up 3 points for the test. If you've been quoted 6%, the calculator tests at 9%. Lenders do the same, at their own test rates, so a loan isn't approved on a repayment you could only just meet today.
The loan is worked back from that repayment. The biggest loan the monthly amount could repay over your term, at the test rate, is the figure you see.
What the 3-point test costs you, in dollars
An illustration, not a client file. One earner on $100,000 a year, spending $3,000 a month, with a 30-year loan quoted at 6%.
| At 6% | Tested at 9% | |
|---|---|---|
| Take-home pay, a month | $6,457 | $6,457 |
| Left after $3,000 of spending | $3,457 | $3,457 |
| Loan that amount could repay over 30 years | about $576,500 | about $429,600 |
The test takes about $147,000 off what the same income could repay at the rate actually charged. And the repayment on the $429,600 loan, at 6%, is about $2,576 a month, well inside the $3,457 that's left. That gap is the point of the buffer: room for rates to rise.
Every regular repayment counts against you at the test rate too. Add a $250-a-month repayment and the figure at 9% falls to about $398,500, about $31,000 less.
Why a lender's figure is usually lower
Income the lender shades.
Overtime, bonuses, commission and rent are often counted at less than their full value, or only with a history behind them. The calculator counts whatever you type.
Card limits.
A lender assesses a repayment on each card's full limit, even one you clear every month.
The lender's view of your spending.
A lender uses its own benchmark for a household like yours when that's higher than what you declare.
Dependants and HECS-HELP.
Each one lowers what a lender counts. The calculator doesn't model either.
Its own test rate.
3 points is APRA's minimum. A lender can test higher.
The six-times-income limit.
Since 1 February 2026, APRA has limited each bank to 20% of new lending to people whose debts are six or more times their income, so a large loan on a modest income has fewer places to go.
How far this can be from a lender's answer
On a plain salary, no dependants and a card limit you've entered honestly, the gap can be small. It widens with every part of your income that isn't base pay, and with every person who depends on you. For self-employed income, shift work or a household with children, treat the figure as the top of the range, not the answer.
No calculator can say how far off it is for you, because the gap comes from the lender's rules, not the arithmetic. Lenders also disagree with each other, so the same figures can borrow noticeably more at one lender than another.
Borrowing calculator questions
A borrowing capacity calculator is only as accurate as the rules it assumes, and every lender's rules differ. Money Brain's calculator shows its working: income after tax, minus repayments and spending, tested at your rate plus 3 percentage points. A lender's figure is usually lower, because it shades some income and uses its own living-cost benchmark.
Got a figure? Find out what it really is.
Send me the figure you got, the income behind it and how it's paid, your debts and card limits, and who depends on you. I'll run it through the lenders that suit your income and tell you what each would lend.
You'll hear back within the hour in business hours, and by 9am the next business day after hours.
Sources
- 1
APRA, Strengthening residential mortgage lending assessments (6 October 2021): serviceability buffer of at least 3 percentage points; held at 3 points in APRA's release of 28 May 2026. Re-read 29 September 2026.
- 2
APRA, debt-to-income limit from 1 February 2026 (release of 27 November 2025). Re-read 29 September 2026.
- 3
Australian Taxation Office, resident income tax rates, 2026–27, and the Medicare levy, as filed in the calculator's tax table.
- 4
The calculator and the illustration: Money Brain's arithmetic on the figures above.
Updated 2 October 2026