Lock the two figures you know — the rest solves live against your rate & buffer.
A serviceability estimate from your income & expenses — the way a lender stress-tests you at 9.00%. An approximation for planning, not a bank's exact number.
| Year | Interest | Principal | Balance |
|---|
Assessment rate. Lenders stress-test your serviceability at your interest rate plus a buffer (APRA's guidance is +3%). Assessment rate = rate + buffer.
Repayment capacity. When you lock a repayment, it's treated as your assessed repayment by default — the figure tested at the assessment rate. That's why raising the buffer lowers the loan you can support. Switch to Actual @ rate to instead lock what you'd really pay at today's rate (the buffer then won't change the loan).
Repayments are principal & interest, amortised over the full term: M = L·i / (1 − (1+i)⁻ⁿ), where i is the periodic rate and n the number of payments. The reverse (loan from repayment) inverts the same formula.
LVR = loan ÷ property value. Above 80% most lenders charge Lenders Mortgage Insurance (LMI), which isn't included here. Cash to settle = deposit + upfront costs.
Borrowing power is estimated the way Australian lenders test serviceability: gross income is taxed to net (ATO FY2024-25 brackets + Medicare + LITO), non-base income shaded to ~80%, living expenses floored to the Household Expenditure Measure (HEM), and credit-card limits counted at 3.8%/mo. The leftover monthly surplus is serviced at the assessment rate over the term to give a maximum loan, then capped at ~6× gross income (APRA's debt-to-income limit). You can't call CBA's calculator (no public API; CORS + their terms block it), so this replicates the public methodology — it's an approximation, typically within ±10–15% of a real assessment, not CBA's exact number.
Estimates only — for planning, not financial advice. Actual lender policies, HEM tables, tax and rates vary and change over time.