Enter what you earn, what you spend and how much headroom you want to keep, and this works out the loan those figures support.
It is not a borrowing capacity. Lenders assess against a household expenditure benchmark that is licensed and unpublished, so nobody outside a lender can reproduce their number — what you get here is an answer that is true given assumptions you can inspect.
Solves for the loan a set of assumptions you control will support — income, declared expenses, commitments, an assessment buffer and a surplus you want to keep.
Which set applies depends on the jurisdiction and the date you enter. Sources last checked 2026-08-30.
Commonwealth — Income tax
1 July 2024 to 30 June 2026
Income Tax Rates Act 1986 (Cth), Schedule 7 Part I — Resident taxpayers
Commonwealth — Income tax
1 July 2026 to 30 June 2027
Income Tax Rates Act 1986 (Cth), Schedule 7 Part I — Resident taxpayers
Commonwealth — Income tax
1 July 2027 onwards
Income Tax Rates Act 1986 (Cth), Schedule 7 Part I — Resident taxpayers
Commonwealth — Medicare levy
1 July 2026 onwards
Gross taxable income
Income before tax for everyone applying. Tax and the Medicare levy are computed from the statutory rate scale rather than estimated, so a pay rise that crosses a bracket is handled properly.
Declared living expenses
What the household actually spends, excluding rent you would stop paying and excluding the loan repayment. Be honest with yourself here: understating it produces a larger number and a worse outcome.
Credit card limits
Limits, not balances. A card you never use still represents money you could draw tomorrow, which is why the limit rather than the balance drives the assessed commitment.
Assessment buffer
Added to your rate before the repayment is worked out, so the scenario is tested above what you would pay. Prudential rules require lenders to apply a buffer of their own; this one is your assumption about how conservative to be.
Surplus to keep
Money you want left each month after everything. Setting it to zero produces the largest number and the tightest life.
The headline is the loan the surplus supports at the buffered rate. Below it are two repayments: the one the scenario was tested against, and the smaller one you would actually pay at the rate you entered. The gap between them is your margin if rates rise.
A result of zero is not a failure of the calculator. It means the figures you entered leave nothing after commitments and the surplus you asked to keep, which is information worth having before you go looking for a lender.
Change one input at a time. The two that move the answer most are the buffer and the declared expenses, and seeing how much they move it is the point of doing this yourself rather than being handed a number.
Every figure below is computed by the same calculator on this page, from the inputs described. Nothing here is typed in by hand, so an example cannot disagree with the tool.
Notice the distance between the tested repayment and the one at the rate entered. That gap is the whole purpose of a buffer: it is the room the household has if rates move against them.
Unused limits cost a surprising amount of borrowing. Cancelling cards before applying is the cheapest change most applicants can make, and this is the arithmetic that shows why.
A far larger figure, and a far more fragile one. Comparing this against the buffered scenario shows what the buffer is actually protecting against, and why lenders are required to apply one.
Net income comes from applying the statutory rate scale and the Medicare levy to the taxable income you entered. Income you mark as already net is added without being taxed again.
Commitments — living expenses, existing repayments, a share of your card limits, and the surplus you want to keep — are subtracted. What remains is the repayment the household can support.
That repayment is then inverted through the standard annuity formula at the buffered rate over the term, which gives the principal it services. The inversion is exact rather than searched for, so the same inputs always give the same figure.
How every calculator on this site is built · Regulatory sources
Your expenses, not a benchmark
Nothing you enter is compared against a spending standard. The measure lenders use for that is commercially licensed, and a substitute assembled from plausible averages would be a policy invented here and presented as a finding.
One rate for the whole term
The repayment assumes the rate you entered holds. It will not. That is what the buffer is for, and why the tested repayment is shown next to the actual one.
No lender product rules
Nothing here knows about maximum loan-to-value ratios, postcode restrictions, employment history requirements, or the treatment of bonus and overtime income. Those decide real applications and none of them is arithmetic.
It is not a pre-approval
No lender has seen these figures and none has agreed to anything. Treat the answer as a planning number and get a real assessment before you bid.
Deposit is a separate constraint
This asks whether you can service a loan. Whether you have the deposit and costs to complete a purchase is a different question, and the maximum purchase price calculator is where it is answered.
Mortgage insurance is not included
A smaller deposit usually means an insurance premium, which is not modelled here because premiums are not published. It reduces what you can buy.
Works out the highest price you can complete on, given what you can borrow and the cash you have, once transfer duty and purchase costs are paid out of the same money.
Puts income and every expense on one cycle and shows what is left: surplus a week, a month and a year, the share of income going to housing, and where the money actually goes.
Shows what a lenders mortgage insurance premium you have been quoted does to your loan: the repayment, the loan-to-value ratio, and what capitalising it costs in interest.
This calculator can be embedded on a business website, branded to match it, with a call to action that sends the enquiry to that business rather than collecting anything here.