Getting approved for an investment property loan usually comes down to one number: what a lender’s serviceability calculation says you can afford to repay. Rental income feeds into that number — but not in the way most first-time investors expect. A lender doesn’t add your expected weekly rent to your income and stop there.

It cuts the rent back first, then tests the whole loan against a stress rate that’s higher than what you’d actually pay. Here’s how rental income is actually factored in, based on the same prudential and responsible-lending framework that applies to every residential mortgage in Australia (this guide assumes you already know the basics of how property investment works — it focuses specifically on the borrowing-power question).

How much of my rental income actually counts?

Less than the full amount. As at July 2026, the Australian Prudential Regulation Authority’s guidance for banks and other authorised deposit-taking institutions (ADIs) describes a standard practice of discounting — or “shading” — expected rental income before it’s counted toward your borrowing power:

“In APRA’s view, prudent serviceability policies incorporate a minimum haircut of 20 per cent on expected rental income, with larger haircuts appropriate for properties where there is a higher risk of non-occupancy.” — APRA, Prudential Practice Guide APG 223

In plain terms: if a property might rent for $500 a week, a lender applying this guidance would count roughly $400 or less of it toward your servicing capacity, with a bigger cut for properties it sees as more likely to sit vacant.

It’s worth being precise about what this guidance is and isn’t. APG 223 is a prudential practice guide — APRA itself notes that practice guides “do not themselves create enforceable requirements.” So this isn’t a law that fixes every bank’s haircut at exactly 20%; it’s APRA describing what it considers prudent, and individual lenders set their own policies from that floor. Some shade rent by more than 20%, particularly for property types they see as harder to keep tenanted. Rental income sits inside a broader category the same guidance covers: non-salary income generally — bonuses, overtime, commissions and other investment income — which APRA also describes as commonly discounted by at least 20%.

Why don’t lenders count the full rent?

Two reasons sit behind the haircut, and both are about risk rather than doubt in your judgment as a buyer.

The first is vacancy and non-payment risk. A property between tenants earns nothing, and even a well-managed property can have arrears or a slow re-let. The haircut builds a margin for those gaps directly into the sum, rather than assuming the rent flows in every single week for the life of the loan.

The second is where the rent figure comes from in the first place. The same APRA guidance notes that ADIs “would normally place less reliance on third-party estimates of future rental income than on actual rental receipts from a property.” A property that’s already tenanted, with a lease and a payment history, gives a lender something it can verify. A property manager’s appraisal of what a place could rent for is a forecast, and lenders treat forecasts more cautiously than receipts.

On top of the haircut, a prudent lender also looks at what it costs to hold the property — the guidance specifically calls out fees and expenses such as strata levies. Ongoing property-management fees are one of the bigger recurring costs: REIQ (Queensland’s peak real estate body) puts typical ongoing management fees at roughly 5–12% of weekly rent nationally, commonly landing around 7–10%, on top of a separate one-off letting fee when a new tenant signs. None of that is rent you get to keep, so it’s part of the picture a lender is weighing alongside the haircut, not instead of it.

Does my actual rent matter more than an agent’s appraisal?

Generally, yes. If you already own the property and it’s tenanted, actual rental receipts — bank statements, a current lease — give a lender verified numbers to work with. If you’re buying a property and it isn’t tenanted yet, the lender has to rely on a rental appraisal instead, and that’s exactly the kind of third-party estimate the guidance above treats more cautiously than real receipts.

Practically, this means an existing landlord adding a second investment property is often working with a stronger, more verifiable rental-income figure than someone buying their first investment property off a written appraisal. It doesn’t change the haircut itself, but it can change how much a lender is prepared to lean on the number at all.

How does rental income fit into the rest of the borrowing-power calculation?

Rental income (after the haircut) is only one input. It’s added to your other income, and the total picture is then tested under Australia’s responsible-lending framework.

Under ASIC’s Regulatory Guide 209 (Credit licensing: responsible lending conduct), a lender must make reasonable inquiries about your income and expenses, take reasonable steps to verify that information, and assess whether you could meet the repayments without substantial hardship. RG 209 doesn’t hand down one fixed formula — what’s “reasonable” scales to your circumstances and the product.

Expenses are commonly sanity-checked against the Household Expenditure Measure (HEM), a quarterly benchmark published by the Melbourne Institute. RG 209 is direct about what a benchmark is for: it “do[es] not provide any information about the individual consumer, and do[es] not confirm or verify that the information that has been obtained about the consumer is true.” Its legitimate uses are things like plausibility-testing expenses that can’t otherwise be verified — not replacing your actual, verified figures with a generic number. If your real expenses are lower and verified, RG 209 says the benchmark needn’t be treated as a floor.

Then comes the interest rate buffer. Under APRA’s Prudential Standard APS 220, as relayed in APG 223, “ADI’s must apply a buffer over a loan’s interest rate of at least 3.0 per cent, unless determined otherwise by APRA” — and that buffer is applied to new and existing debts, including any other mortgages you hold. So the whole repayment test runs at a rate roughly 3 percentage points above what you’d actually pay today, not today’s rate itself. Your discounted rental income has to help the sum clear that higher bar, not just today’s actual repayment.

Are investment loans assessed on a different set of rules to a home loan?

No — they sit inside the same regulatory architecture, just entered through a different legal gate. RG 209 states plainly that responsible-lending obligations apply to “home loans, reverse mortgages, residential investment loans, personal loans, credit card contracts” and more, on the same footing.

The National Credit Code separates the two by purpose, not by giving investment loans a lighter or heavier regime: an owner-occupier loan is for “personal, domestic or household purposes,” while a loan “to purchase, renovate or improve residential property for investment purposes” is expressly carved out as investment borrowing in its own right (the Code states outright that “investment by the debtor is not a personal, domestic or household purpose”). Either way, it’s regulated credit, and the same RG 209 inquiries, the same HEM-style benchmarking and the same APS 220 buffer apply. The rental-income haircut is the investor-specific layer added on top of that shared framework — not a separate set of rules replacing it.

One thing that does typically differ, on average, is the interest rate itself: as at July 2026, RBA data (Table F6, May 2026) shows investors paying around 0.2 percentage points more than owner-occupiers on outstanding home loans. That’s a system-wide average, not a rule any one lender must follow, and it applies on top of the buffer above, not instead of it — a slightly higher starting rate plus the same 3-point-or-more buffer.

Exact numbers beyond these regulator-level settings — a specific lender’s rental haircut above the 20% floor, its maximum loan-to-value ratio for investment purchases, or any debt-to-income limit it applies — are that lender’s own credit policy, set within this shared framework. They vary between institutions, which is exactly why comparing more than one lender (or using a broker who can) tends to matter more for investment loans than for a standard owner-occupier purchase.

If qualifying for a big enough loan is the part holding you back, it’s worth knowing a mortgage isn’t the only way to hold property directly. Fractional investing — buying a slice of a property rather than the whole thing outright — sits outside this loan-serviceability process altogether, because you’re not borrowing to acquire your share.

Does choosing interest-only repayments change my borrowing power?

Not in the way it might look on paper. As at July 2026, APRA doesn’t impose a numeric cap on interest-only (IO) lending. There’s a piece of history worth knowing here: in March 2017, APRA wrote to ADIs expecting them to “limit the flow of new interest-only lending to 30 per cent of total new residential mortgage lending” — a temporary supervisory benchmark, not a permanent rule. APRA confirmed its removal in a December 2018 release, phased out for different ADIs through into 2019, once new IO lending had already fallen well below that level.

Today, APG 223 sets out risk-management expectations instead of a reinstated numeric limit — for example, that IO periods should be “of limited duration, particularly for owner-occupiers,” and that interest-only loans “may not be appropriate for all borrowers.” The detail that matters most for borrowing power: a prudent serviceability assessment “would incorporate the borrower’s ability to repay principal and interest over the actual repayment period” — meaning the loan is tested as if you were making full principal-and-interest repayments over what’s left of the loan term, not just the lower interest-only amount. Choosing interest-only can ease your cash flow in the short term, but it isn’t a lever for increasing how much you’re assessed as able to borrow.

Does every lender apply these rules the same way?

No, and that’s worth restating plainly: everything above — RG 209, HEM, the APS 220 buffer, the rental-income haircut — describes the shared regulatory floor every lender in Australia operates within. Where any individual lender sets its own numbers above that floor (its exact haircut, its investment-property LVR limits, its own rate) is its own credit policy, and those vary. A mortgage broker who deals with multiple lenders, or the lenders themselves, can tell you the actual figures that would apply to a specific property and your own financial position — this article can only describe the framework, not any one lender’s numbers.

Quick reference: key terms

Term	What it means
Borrowing power	The amount a lender calculates you could responsibly borrow, based on income, expenses, existing debts and buffers — not simply what you’d like to borrow
Serviceability assessment	The lender’s process, required under responsible-lending law, for testing whether you could keep meeting repayments
Rental income shading (haircut)	Reducing a property’s expected rent by a set percentage before counting it as income, to allow for vacancies and costs
HEM (Household Expenditure Measure)	A quarterly benchmark of typical household spending, used to plausibility-test — not replace — your declared expenses
Interest rate buffer	An extra margin (at least 3.0 percentage points under APS 220) added to the loan’s actual rate when testing serviceability

Getting a clearer read on your own numbers

The framework above tells you how the calculation works. The actual figures — what rent a specific property might achieve, what a specific lender will count, and what that means for your own borrowing power — depend on your income, your existing debts and the property itself. A recent, realistic rental appraisal (or an existing lease if the property is already tenanted) and a conversation with a mortgage broker or lender are the two most useful next steps for turning this framework into an actual number. If you’re still working out what a property might rent for in the first place, our guide to calculating gross and net rental yield walks through both formulas.