Borrowing power is the number everything else hangs off: it sets your price range, your suburb list and your timeline. It is also widely misunderstood, because the figure a quick online calculator produces and the figure a lender will actually approve can be tens of thousands of dollars apart. Here is what genuinely drives the number, and what moves it.

What do lenders assess?

Every lender runs a version of the same equation: income they will accept, minus living expenses, minus commitments, tested at a buffered interest rate, produces a repayment capacity, which converts to a maximum loan.

  • Income. Base salary counts in full. Overtime, allowances, bonuses and commission are often counted at a discount or averaged over one to two years, and policies differ sharply between lenders, enough that the right lender choice changes the answer. If this is you, the guide to overtime and allowance income goes deeper.
  • Living expenses. Lenders use the higher of your declared expenses or a statistical benchmark scaled to your income and household. Cutting discretionary spending in the months before applying genuinely helps, both the number and the story your statements tell.
  • Existing commitments. Car loans, personal loans and buy-now-pay-later commitments reduce capacity dollar for dollar of repayment. Credit cards reduce it by a share of the limit, not the balance: a $20,000 limit you never touch still costs you borrowing power with most lenders.
  • HECS/HELP debt. Repayments scale with income and are treated as a commitment. For many graduates this is the single biggest surprise in the assessment; the HECS and home loans guide covers strategies.
  • The buffer. Lenders test your repayments at roughly 3% above the actual rate, the serviceability buffer. You are being assessed on whether you could still pay if rates rose, which is why capacity feels lower than your budget suggests.

Why do online calculators disagree with lenders?

A generic calculator does not know which lender’s income policy applies to you, uses average expense assumptions, and cannot see your credit file. Treat it as a compass, not a contract. The gap runs both ways: buyers with clean finances and simple income are sometimes approved for more than the generic number, buyers with cards and complications for less.

What lifts borrowing power?

  • Close or cut credit cards. Reducing a limit helps immediately; closing unused cards helps more.
  • Clear small debts. A car loan with a year to run can cost far more in capacity than it would cost to pay out.
  • Choose the lender to fit your income. Casual, contract, self-employed, overtime-heavy: each has lenders that assess it generously and lenders that do not.
  • Buy with someone. Two incomes assessed together usually beat one, with legal and practical considerations covered in the buying with a partner guide.

Should you borrow the maximum?

The maximum a lender will approve and the loan you will live comfortably with are different numbers. Repayments you can sustain while still saving, travelling and absorbing a rate rise are worth more than an extra bedroom financed at the edge of capacity. Decide your own comfortable repayment first, then work backwards to a price.

How does the calculation work with real numbers?

To make the assessment concrete, imagine a household earning $120,000 before tax with no debts. A lender starts with net income, subtracts living expenses, which it sets at the higher of what you declare and a benchmark scaled to your income and household size, and subtracts any existing repayments. What remains is the amount available each month for a home loan. The lender then asks what loan that monthly amount supports, not at today’s rate but at a rate roughly three percentage points higher, over a thirty-year term. The loan size that falls out of that test is your borrowing power with that lender.

Every step in that chain is a place where two lenders can differ: how much of variable income they count, which expense benchmark they apply, what share of a credit card limit they treat as a commitment, and occasionally the buffer itself. That is why the spread between the most and least generous lender for the same applicant is routinely large enough to change the suburb you can buy in, and why choosing the lender is part of the answer to the question rather than something that happens after it.

How do deposit and borrowing power fit together?

A common confusion is to treat the deposit as the constraint when it is the loan that binds, or the reverse. Borrowing power tells you the largest loan a lender will make; your deposit tells you how much property that loan can reach. A buyer with a $40,000 deposit and $700,000 of borrowing power can reach about $740,000 under the 5% scheme. A buyer with a $200,000 deposit but $500,000 of borrowing power reaches $700,000 with a much larger equity cushion. Both numbers need to be known before the price range is set, which is why our first home buyer process starts with both at once.

What should you change three months before applying?

  • Spending. Lenders read three to six months of statements. Regular gambling transactions, buy-now-pay-later commitments and repeated overdrawn fees all read badly; a visible savings pattern reads well.
  • Card limits. Reduce limits to what you actually use and close cards you do not. The effect on assessed capacity is immediate.
  • Small loans. A personal or car loan with a small balance but a high repayment is often worth paying out, because the lender counts the repayment, not the balance.
  • Income documentation. If your income includes overtime, allowances or bonuses, gather the history now. Lenders that count these generously want to see it over time, and the overtime and allowances guide explains what each needs.

Why does the answer change between lenders?

Four policy differences account for most of the spread. The first is variable income: one lender counts 80% of regular overtime averaged over a year, another counts all of it, a third wants two years of history. The second is expenses: lenders use different benchmark tables, and some scale them more steeply with income than others. The third is credit cards: most lenders count a share of the limit as a monthly commitment, but the share varies, so the same $20,000 limit costs more capacity with some lenders than others. The fourth is debts near the end of their term: some lenders ignore a loan with only a few months to run, most do not. A buyer whose situation touches two or three of these can see a difference between lenders that amounts to a meaningful slice of a Sydney deposit, which is the reason a broker runs your figures across the panel rather than into one bank’s calculator.

Questions people ask

Does HECS really reduce how much I can borrow?

Yes. Compulsory HELP repayments are deducted from income in the serviceability calculation, so a graduate with a HELP debt is assessed as having less available income than a colleague on the same salary without one. Whether to repay it early is a separate question, covered in the HECS and home loans guide.

Does a bigger deposit increase my borrowing power?

Not directly. Borrowing power is about repayment capacity, not deposit. A bigger deposit does widen your lender choice and can unlock sharper pricing, which slightly improves the number, but it does not change the income the assessment is based on.

Why did two calculators give me very different numbers?

Because they assumed different lenders’ policies, different expense benchmarks and different buffers. Neither is wrong; neither is an approval. The real figure comes from an assessment against the policy of the lender you would actually apply to.

For a quick range, run the borrowing power calculator. For the real number, against actual lender policies with your actual documents, the free borrowing assessment is the honest version, and it costs nothing but half an hour.

Sources: APRA, serviceability buffer of 3 percentage points (APS 220, kept on 28 May 2026); Housing Australia, 5% Deposit Scheme, checked 17 October 2026.

General information only, not credit, legal or tax advice. Your situation is assessed properly before any recommendation. Government scheme details change; figures are current at the time of writing.