Estimate how a principal-and-interest repayment changes if the entered rate rises by 0.5 to 4 percentage points. The result is a planning estimate, not a lender serviceability test, approval or personal affordability assessment.
Loan: $700,000. Current rate: 6.35%. Term: 30 years. Base monthly repayment: $4,356.
| Scenario | Stressed rate | Monthly repayment | Extra per month | Extra per year |
|---|---|---|---|---|
| Current | 6.35% | $4,356 | $0 | $0 |
| +0.5 pp | 6.85% | $4,587 | $231 | $2,774 |
| +1.0 pp | 7.35% | $4,823 | $467 | $5,606 |
| +2.0 pp | 8.35% | $5,308 | $953 | $11,430 |
| +3.0 ppbuffer illustration | 9.35% | $5,810 | $1,454 | $17,446 |
| +4.0 pp | 10.35% | $6,325 | $1,969 | $23,630 |
APRA confirmed on 28 May 2026 that the mortgage serviceability buffer for authorised deposit-taking institutions remains at 3 percentage points. At 3 percentage points above the rate entered, the mathematical repayment is $5,810 per month at 9.35%, or $17,446 more per year than the base scenario.
This does not reproduce a lender assessment. A lender also considers verified income, living expenses, other debts, credit limits, loan features and its own credit policy. APRA's portfolio rules do not determine the result of an individual application.
Review the repayment difference alongside after-tax income, essential spending, other debt payments and irregular costs. This page does not model an income drop or tell you which buffer is suitable. If you are struggling with repayments, contact your lender's hardship team or the National Debt Helpline.
The standard amortisation formula: M = P x r(1+r)n / ((1+r)n - 1), where P is the principal, r is the monthly rate (annual / 12), and n is the total number of monthly payments. Each scenario re-solves M against a different rate. Actual lender repayments can differ because of daily interest, fees, repayment timing and product features. Compare the method with ASIC Moneysmart.
Last reviewed: 1 August 2026.