Mortgage stress test calculator
APRA expects banks to check you could still afford your loan if the rate were 3 percentage points higher. This calculator shows your repayment at your rate and at that buffer rate: on a $600,000 loan at 6.24% over 30 years, the repayment rises from about $3,690 to $4,932 a month. It also shows your repayments after rate rises of 0.25 to 3 percentage points, and the share of your income they would take.
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Mortgage stress test calculator
Your repayments after rate rises and at the APRA buffer rate (+3 percentage points).
Before tax. Shows the share of income your repayment takes.
At 6.00%
$2,998
a month
At 9.00% (buffer)
$4,023
+$1,025 a month
| Rate rise | New rate | Repayment a month | Increase |
|---|---|---|---|
| +0.25 points | 6.25% | $3,078.59 | +$81 |
| +0.50 points | 6.50% | $3,160.34 | +$163 |
| +1.00 points | 7.00% | $3,326.51 | +$329 |
| +2.00 points | 8.00% | $3,668.82 | +$671 |
| +3.00 points | 9.00% | $4,023.11 | +$1,025 |
At your rate the repayment is 30.0% of your gross income. That is within 30%, a common benchmark for housing stress.
At the buffer rate it would be 40.2%. That is above 35%, our rough check on the buffered repayment, so expect a lender to look closely at your expenses and debts.
Principal and interest, monthly. The 30% and 35% figures are rules of thumb, not APRA or lender rules: lenders assess what is left of your income after tax, living expenses and other debts. See how much you can borrow for that calculation.
What is the APRA serviceability buffer?
The Australian Prudential Regulation Authority (APRA) expects banks and other authorised deposit-taking institutions to assess new borrowers' ability to repay at an interest rate at least 3 percentage points above the loan's product rate. APRA raised the buffer from 2.5 to 3 percentage points on 6 October 2021, and in its 27 November 2025 announcement confirmed it would stay at three.
The buffer isn't the rate you pay. It is a what-if test: if your loan rate is 6.24%, the lender checks you could manage repayments at 9.24%. It applies to new loans, including refinances to a new lender, which is why some borrowers find they can't refinance a loan they are comfortably paying today.
| Setting | Level | Since |
|---|---|---|
| Mortgage serviceability buffer | At least 3 percentage points above the loan rate | 6 October 2021 (raised from 2.5); confirmed 27 November 2025 |
| Debt-to-income (DTI) limit | No more than 20% of a bank's new mortgage lending at a DTI of 6 or more, owner-occupier and investor lending measured separately | 1 February 2026 |
How the calculator works
It calculates the monthly principal and interest repayment on your loan amount and term at your rate, then again at your rate plus 3 percentage points, using the standard amortisation formula. If you enter your gross monthly income, it compares the buffered repayment with 35% of that income.
That 35% is a rule of thumb for a quick check, not an APRA rule or any particular lender's policy. A real assessment starts from your after-tax income, subtracts your living expenses and the repayments on all your debts (at the buffered rate for the new loan), and checks that a surplus remains. If you're close to the line in this calculator, expect a lender to look closely.
| Loan amount | At 6.24% | At 9.24% (buffer rate) | Difference |
|---|---|---|---|
| $500,000 | $3,075 | $4,110 | $1,034 |
| $600,000 | $3,690 | $4,932 | $1,241 |
| $700,000 | $4,305 | $5,754 | $1,448 |
How much repayments rise when rates go up
Every 0.25 percentage point rise adds roughly $98 a month to a $600,000 loan over 30 years. The table shows rises up to the 3 point buffer on three common loan sizes; enter your own loan in the calculator for your figures.
| Rate rise | New rate | $500,000 | $600,000 | $700,000 |
|---|---|---|---|---|
| Today | 6.24% | $3,075 | $3,690 | $4,305 |
| +0.25 points | 6.49% | $3,157 (+$82) | $3,788 (+$98) | $4,420 (+$114) |
| +0.50 points | 6.74% | $3,240 (+$164) | $3,888 (+$197) | $4,536 (+$230) |
| +1.00 points | 7.24% | $3,407 (+$332) | $4,089 (+$399) | $4,770 (+$465) |
| +2.00 points | 8.24% | $3,753 (+$677) | $4,503 (+$813) | $5,254 (+$948) |
| +3.00 points | 9.24% | $4,110 (+$1,034) | $4,932 (+$1,241) | $5,754 (+$1,448) |
What is mortgage stress?
Mortgage stress usually means housing costs taking more than 30% of a household's gross income. There is no single official definition, but the ABS measures housing affordability as housing costs divided by gross household income, and reports how many lower income households spend more than 30%. In its 2019–20 survey that was around 37% of lower income owners with a mortgage.
The calculator shows your repayment as a share of gross income at your current rate, against that 30% benchmark, and at the buffer rate, against our rougher 35% check. Neither is how a lender decides: lenders work from your income after tax, your living expenses and your other debts, which the borrowing power calculator models.
The DTI limit: the second test since February 2026
From 1 February 2026, APRA limits each bank's new lending at a debt-to-income ratio of six or more to 20% of its new mortgage lending, with owner-occupier and investor lending measured separately. Your DTI is your total debt (including the new loan) divided by your gross annual income: $600,000 of debt on a $100,000 income is a DTI of 6.
It isn't a hard cap on any one borrower, and APRA expected it to have little near-term effect. In the June quarter 2026, 5.6% of banks' new loans had a DTI of six or more (3.7% of owner-occupier loans and 8.9% of investor loans). But a bank close to its 20% allowance may be less willing to approve high-DTI applications.
If you don't pass the stress test
Borrow less
A bigger deposit or a cheaper property reduces both your repayment and your buffered repayment.
Pay down other debts
Car loan, personal loan and credit card commitments reduce the surplus a lender calculates, so clearing or closing them helps.
Choose a longer term
A 30-year term has lower repayments than 25 years, at the cost of more total interest.
Find a lower rate
The buffer is added to the loan's rate, so a lower rate lowers the assessment rate too.
Add a co-borrower's income
A second income can lift your assessed surplus, but both of you are then liable for the whole loan.
Review your expenses
Lenders must make reasonable inquiries about your living costs, so know your real monthly spending before you apply.
Stress test questions
What is the APRA serviceability buffer?
APRA expects the banks it regulates to assess whether you could afford your loan at an interest rate at least 3 percentage points above the loan's rate. It raised the buffer from 2.5 to 3 percentage points in October 2021 and confirmed it at 3 in November 2025.
Do non-bank lenders use the 3% buffer?
APRA's buffer applies to authorised deposit-taking institutions (banks, credit unions and building societies). Non-bank lenders aren't regulated by APRA, but they still have to meet the responsible lending obligations in the National Credit Act and set their own assessment rates.
What is the DTI limit?
Since 1 February 2026, no more than 20% of a bank's new mortgage lending can go to loans at a debt-to-income ratio of six or more, measured separately for owner-occupier and investor lending. Your DTI is your total debt divided by your gross annual income.
What is mortgage stress?
There is no single official definition. A common benchmark is housing costs of more than 30% of gross household income, which is how the ABS reports housing affordability for lower income households. The calculator shows the share of your income your repayment takes at your rate and at the buffer rate.
How much will my repayments go up if rates rise by 0.25%?
On a $600,000 loan at 6.24% over 30 years, about $98 a month. The table on this page shows rises of up to 3 percentage points on $500,000, $600,000 and $700,000.
What do the 30% and 35% in this calculator mean?
Both are rules of thumb, not APRA or lender rules. 30% of gross income at your current rate is a common housing stress benchmark; 35% at the buffer rate is our rough check on whether a lender would look closely. Real lender assessments subtract tax, your living expenses and other debt repayments from your income and check what is left.
How much do you need to earn for a $700,000 mortgage?
At the buffer rate of 9.24% (6.24% plus 3), a $700,000 loan over 30 years costs about $5,754 a month. A lender needs to see that your income after tax, living expenses and other debts covers that. Your DTI would be under 6 on an income of about $117,000 or more if the mortgage is your only debt. Our borrowing power calculator turns your own figures into an indicative range, and questions about age and loan terms are covered in our guide to home loans for older borrowers.
