Borrowing Power Calculator Australia — How Much Can I Borrow 2026

Estimate the maximum a lender would let you borrow, using the same inputs lenders run themselves: income, household expenses, existing debts, deposit, and APRA's serviceability buffer. Built for Australian borrowers in 2026.

How lenders calculate your borrowing capacity

Despite the marketing, every Australian lender uses the same skeleton calculation. The differences are in the dials, not the engine.

The framework is Net Income Surplus (NIS): assessed income minus assessed expenses minus existing commitments minus the proposed loan repayment must be greater than zero (with a small buffer). Pseudo-formula:

Assessed gross income
− Income tax & Medicare levy
− Living expenses (HEM or stated, whichever is higher)
− Existing debt commitments
− Proposed loan repayment at (rate + 3% APRA buffer)
= Net Income Surplus (must be ≥ 0)

The maximum loan is the largest principal that still produces a non-negative NIS. Move any input — extra income, lower expenses, lighter debt load — and the maximum shifts.

What lenders don't tell you in headline calculators is the size of the assumptions: income shading (only 80% of overtime/bonus counts at most lenders), expense flooring (HEM beats your stated number if HEM is higher), and the 3% rate buffer (sometimes more for investment loans). All three reduce the answer.

The HEM (Household Expenditure Measure) explained

HEM is the benchmark Australian lenders use as a floor on living expenses. It's a single number per applicant profile, derived from the ABS Household Expenditure Survey by the Melbourne Institute. Lenders adjust HEM by:

• Income tier — higher earners are assumed to spend more
• Household composition — single, couple, +1 dependant, +2, etc.
• Postcode — capital city HEMs are higher than regional

If your stated expenses are below your HEM tier, the lender ignores your number and uses HEM. This is why understating discretionary spending doesn't lift borrowing capacity — it just gets overridden.

For a couple earning $200,000 combined with two children in a metro postcode, HEM typically lands around $5,500–$6,500 per month. If you genuinely spend less, document it (six months of bank statements showing the lower run-rate) and a broker can sometimes negotiate a lender that accepts a stated number below the published HEM tier.

The 3% APRA serviceability buffer

Since October 2021, APRA has required lenders to assess loan serviceability at the actual interest rate plus a 3% buffer. So if you're being offered a loan at 6.0%, the lender tests whether you could afford repayments at 9.0%.

The buffer matters because it amplifies the effect of every other input. On a $700,000 loan over 30 years:

• At 6.0% the actual repayment is ~$4,200/month
• At 9.0% (the assessed rate) it's ~$5,640/month
• The difference — $1,440/month — has to fit inside your NIS

This is why a small income lift or a debt payoff can unlock a disproportionately large increase in borrowing power: it's the assessed repayment at the buffered rate, not the actual repayment, that's binding.

Some lenders apply a tighter buffer (2%) for refinancers swapping like-for-like to reduce mortgage prisoners — worth knowing if you're rate-shopping an existing loan.

Why two lenders give different numbers for the same applicant

The framework above is universal; the dials inside it are not. Every lender sets its own:

• Income shading — 80%, 90%, or 100% of variable income (overtime, bonus, commission, rental income) counts
• Commitment factor — credit card limits assessed at 3.0%, 3.8%, or 5% of the limit per month
• HEM tier — different lenders use different HEM tier maps for the same income/postcode
• Investment property treatment — some lenders haircut rental income by 80%, some by 75%, some net it of expected expenses

The combined effect of these dials can swing a borrowing capacity estimate by $150,000–$250,000 between lenders for the same applicant. This is the structural reason brokers add value: they know which lender's policy quirks are most favourable for the income profile in front of them.

How existing debts affect your capacity

Every dollar of monthly debt commitment is a dollar that can't service the new home loan. The biggest hits:

• HECS-HELP — full annual repayment counted. From 2025–26 a new marginal system applies: 15% of income above the $67,000 threshold (so $3,450/year on a $90k salary, far less than the old flat-rate system). Reduces capacity by $40,000–$70,000.
• Credit cards — typically 3.0–3.8% of the limit, not the balance. A $20,000 limit reads as a $600–$760 monthly commitment even with a zero balance.
• Personal loans, car finance, novated leases — full contracted repayment counted.
• BNPL (Afterpay, Zip, Klarna) — treatment varies; some lenders look at usage history, others at the limit, others at recent monthly average. Trending stricter.

The fastest tactical move before applying: close any credit cards you don't actively use, and lower the limits on the ones you keep. A cleanup of $30,000 in unused credit limits can lift borrowing capacity by $90,000+.

How to increase your borrowing power

In rough order of speed-to-impact:

1. Reduce credit card limits — fastest. Lower limits = lower assessed commitment.
2. Pay down and close BNPL accounts — second fastest, especially with conservative lenders.
3. Discharge personal loans — direct dollar-for-dollar capacity lift.
4. Lengthen the loan term to 30 years — lower assessed monthly repayment.
5. Demonstrate sustained expense reduction — six months of statements showing tighter spending lets a broker push back on HEM.
6. Lift documented variable income — bonus letters, two years of consistent overtime, formalised rental agreements.
7. Shop the right lender — broker territory; the structural lender-by-lender dial differences described above.

Borrowing as a couple vs as a single applicant

Joint applications combine both incomes, both debt loads, and apply a household HEM (typically 1.4–1.6× a single HEM, not 2×). The arithmetic usually means:

• A couple borrows more than each could alone, but less than 2× what one could
• The lower-earning partner's HECS, credit limits, and debt load weigh on the joint application even if the application is "in their name only" (it isn't — both files are pulled)
• Income from one partner can be used to service a mortgage in the other's name on a "single-applicant joint-borrower" structure, but lenders are increasingly cautious here

Run both scenarios in the calculator (single applicant vs joint) to see the trade-off for your specific income split.

The role of a guarantor

A guarantor home loan uses a third party — almost always a parent — to pledge equity in their existing property as additional security. This can:

• Eliminate LMI even when your own deposit is below 20%
• Let you borrow up to 100% (or more, if stamp duty is capitalised) of purchase price
• Speed up market entry by years, especially in capital cities

Important details:

• The guarantor's income is not usually added to yours; only their property equity is offered as additional security
• The guarantee is typically limited to a portion of the loan (commonly 20% of the property value), not the full loan
• The guarantee is released once your loan-to-value ratio drops below 80% on the strength of repayments and capital growth alone
• The guarantor must demonstrate they can service the guaranteed amount if you default — so retired parents on pensions are often unable to act as guarantors

A dedicated guarantor home loan guide covers the legal mechanics and the parent-side implications in more detail.