How our data and calculations work
We believe you deserve to know where our numbers come from and what their limitations are. This page explains our data sources, how prices are calculated, and what we get right and wrong.
Where the suburb data comes from
Our suburb database covers 15,000+ locations across all 8 Australian states and territories. Rent data comes from two sources:
Rental bond lodgements — the official measure (best)
Australian governments treat the median rent of newly lodged rental bonds as the authoritative measure of what a suburb costs to rent — NSW DCJ calls its bond-derived Rent and Sales Report "the sole authoritative source of data on NSW rent movements", and the Queensland RTA and Victorian DFFH publish the same way. We run that data directly for NSW, QLD and VIC, and where we have it, it's the rent we show and the rent our "income needed" figure is based on. It answers the question you're actually asking: what would I pay to sign a lease here now? Following DCJ practice, we don't publish a figure derived from 10 or fewer bonds.
One granularity catch, because it changes how much to trust a number. Queensland and Victoria publish per suburb. NSW publishes per postcode — its bond records carry a postcode, not a suburb name — so a NSW figure is its postcode's median, covering a median of 4 suburbs and sometimes many more. We label NSW figures as postcode medians rather than quietly presenting them as suburb-level. Within a typical postcode the suburbs differ by about 12%, so it's a good guide; but in a postcode that mixes, say, a unit-heavy centre with a semi-rural pocket, the postcode median will suit neither well.
ABS Census 2021 — modelled fallback, calibrated against the bond data
Everywhere else we fall back to the median weekly rent recorded in the 2021 ABS Census, carried forward with state rental CPI growth. Be aware of what that measures: every current tenancy, including long-held leases well below today's market — so on its own it sits below what a new lease costs. We correct for that. Using the 7,823 real bond medians we hold for NSW, QLD and VIC as a ruler, we measured how far the modelled figure falls below a new lease and scaled it back up, fitting on 70% of those suburbs and checking the result on the 30% we held back. Across every suburb where we can check, the modelled rent now sits 2.6% below the real bond median on average, with a typical error of 9.8% — before this calibration it was 47% low. It's still an estimate, not a quote: treat it as the middle of a range, not a number to budget to the dollar.
ABS-calibrated model — estimated data
For suburbs with no Census SA2 match (typically remote areas, industrial zones, or very small communities), we use a calibrated model. It combines ABS 2021 Census income data with state-level baselines, adjusted for distance from the nearest city of any size — not the state capital, which is why Burleigh Waters is now priced as five minutes from the Gold Coast rather than an hour from Brisbane — plus local income levels and population density. Where enough bond data surrounds a city, that city's own rent level is measured directly rather than inferred. These suburbs show "(est.)" throughout the site.
Where this is weakest — WA, SA, TAS, NT and the ACT
Only NSW, QLD and VIC publish open bond data, so those are the only states we can calibrate against directly. The other five borrow the correction fitted from those three. That's a genuine assumption, and we'd rather name it than bury it: if rents in Perth or Adelaide sit differently against the Census than they do on the east coast, our figures there will be off in that direction. Adding the remaining states is on our list.
Where a government publishes real sale prices, we use them. Victoria's Department of Transport and Planning publishes a median house price per suburb, and South Australia's housing department publishes one for metropolitan Adelaide — both from real sales, both open data. In those places the price you see is the real median, marked "Real", and our yield figures are built on it.
Everywhere else — NSW, QLD, WA, Tasmania, the NT, the ACT and regional SA — no open government source publishes suburb-level sale prices, so we fall back to a location-based model calibrated to state medians, marked "Est.". We have nothing to check those against, and now that our rents are calibrated they imply the modelled prices are too low, in some places substantially. Treat an estimated price as a rough guide, never a valuation — and adding real sources for the remaining states is on our list.
How the calculations work
Every calculator is an open formula — shown below exactly as implemented, with a hand-checked worked example. The code behind each is covered by automated known-value tests, so a change that breaks a published figure fails our build.
Rent affordability (30% rule)
Open the calculator →weekly_rent_budget = annual_income × 0.30 ÷ 52
A household is considered in rental stress when it spends more than 30% of gross income on rent — the standard AIHW/Treasury definition. Suburbs where the median rent is below your budget are "affordable"; 30–40% of income is "tight"; above 40% is "out of reach". You can override the 30% default with a custom budget.
Worked example: On $80,000: 80,000 × 0.30 ÷ 52 = $461.54/week.
Buy affordability & repayments
Open the calculator →M = P·r(1+r)ⁿ ÷ ((1+r)ⁿ − 1) where P = price − deposit, r = rate÷12, n = months
The standard principal-and-interest amortisation identity every lender uses. The map assumes a 20% deposit and 25-year term; the repayments calculator lets you set all three inputs. Weekly and fortnightly figures are monthly × 12 ÷ 52 and × 12 ÷ 26. LMI is flagged when the deposit falls below 20%.
Worked example: $600,000 home, 20% deposit, 5.85% over 25 years: P = $480,000 → ≈ $3,046/month. Affordable (≤30% of gross) on incomes above ≈ $121,800.
Borrowing capacity
Open the calculator →assessment_rate = max(your_rate + 3%, 5.5%) · capacity = loan serviceable by your net surplus at that rate
We estimate net income from ATO brackets, subtract declared liabilities (credit cards count at 3.8% of the limit per month, rental income is haircut to 80%) and HEM-style living expenses, then solve for the loan whose repayment your monthly surplus can service at the assessment rate.
Worked example: At a 6.0% headline rate you are assessed at 9.0% — the APRA buffer is why capacity sits well below what the advertised rate implies.
Stamp duty
Open the calculator →duty = state_bracket_schedule(price) − FHB_concessions (+ foreign surcharge if applicable)
All eight state and territory progressive schedules are implemented, including 2025-26 first home buyer exemptions and foreign-buyer surcharges. We update when state budgets change the rates — each schedule's effective date is on the Data Sources page.
Worked example: NSW first home buyer at $850,000: above the $800k full exemption, so the tapered concession to $1M applies.
Lenders Mortgage Insurance (LMI)
Open the calculator →premium ≈ loan × band_rate(LVR, loan_size) × 1.1
LMI applies above 80% LVR. Rates come from standard industry band tables keyed on LVR and loan size; the ×1.1 approximates the ~10% duty most states levy on the premium itself. Actual quotes vary by insurer — treat ours as a guide.
Worked example: A $570,000 loan on a $600,000 home is 95% LVR — a materially higher premium band than 85%.
Rent vs buy
Open the calculator →compare Σ renting_costs vs Σ ownership_costs − equity_built, over your horizon
Renting totals your rent with annual growth. Owning totals repayments, rates, maintenance and transaction costs, minus the equity you build from principal reduction and price growth at the rates you set. The verdict is whichever path leaves you ahead.
Worked example: Short horizons usually favour renting: stamp duty and legals are front-loaded, while equity builds slowly at first.
Refinancing
Open the calculator →break_even_months = switching_costs ÷ monthly_saving
Monthly saving is your current repayment minus the repayment at the new rate over the remaining term (we don't restart the clock). Discharge, application and valuation fees — plus any fixed-rate break cost you enter — make up the switching costs.
Worked example: $1,050 in switch costs against a $210/month saving → break-even in 5 months.
Negative gearing & capital gains tax
Open the calculator →tax_effect = net_rental_loss × marginal_rate · CGT = gain × 50% × marginal_rate (held > 12 months)
Rental losses offset other income at your marginal rate using current ATO resident brackets. Gains on assets held over 12 months receive the 50% individual discount. Assumes individual ownership — company, trust and SMSF structures differ.
Worked example: A $10,000 rental loss at the 37% bracket returns $3,700; a $200,000 discounted gain adds $100,000 to taxable income in the sale year.
Tax calculations
ATO 2025-26 resident brackets + 2% Medicare levy + HECS-HELP thresholds
Take-home income uses the post-Stage-3 brackets effective July 2024. We do not model offsets (LITO) or deductions, so lower-income take-home figures are slightly conservative. Updated each financial year.
Deposit timeline
months_to_save = deposit_required ÷ monthly_savings
Deliberately conservative: no compounding on savings. First Home Super Saver Scheme contributions can meaningfully shorten the timeline via concessional tax treatment.
How often data is updated
| Data type | Source | Frequency |
|---|---|---|
| Suburb median rents (NSW, QLD, VIC) | State rental-bond lodgements — NSW Rental Bond Board, QLD RTA, VIC DFFH | Quarterly |
| Suburb median sale prices (VIC, metro SA) | State land/valuation authorities — VIC DTP, SA DHUD | Quarterly |
| Rents & prices elsewhere (estimated) | ABS 2021 Census + calibrated model | Monthly (model recalibrated) |
| Suburb demographics, amenity & crime | ABS Census & SEIFA, OpenStreetMap, NSW BOCSAR | With each source release |
| Interest rate default | RBA cash rate (rba.gov.au) | Monthly (follows RBA meetings) |
| Stamp duty rules | State government websites | As announced |
| Tax brackets and rates | ATO | Annually (each financial year) |
| Government scheme details | Housing Australia, state websites | As announced |
Honest limitations
We think it's important to be upfront about what this site is not.
- Suburb medians are based on houses. Unit and apartment medians are often 20–40% lower.
- Estimated suburbs use a model, not real transactions. Remote or unusual suburbs may be significantly off.
- Affordability calculations don't account for existing debts, credit history, or lender serviceability buffers (which add 3% on top of the loan rate).
- Stamp duty concession eligibility varies by individual circumstance. Our figures are a guide, not a determination.
- Property markets move quickly. A suburb that was affordable six months ago may not be now.
- This is general information only, not financial or legal advice.
If you need an accurate assessment of your borrowing capacity and costs, we recommend speaking with a licensed mortgage broker. Our broker matching service is free and connects you with MFAA or FBAA registered brokers.
How we make money and stay independent
Being clear about this matters more to us than the revenue does, so here it is plainly.
How we're paid. Some links to services — brokers, insurers, conveyancers, removalists — earn us a referral fee if you use them. Those links are always labelled Paid link where they appear. Links that earn us nothing say so too, because knowing which is which is the point. We also sell a small number of guides, and we show advertising.
What money can and cannot buy. A commercial relationship buys distribution — a listing, a referral link, a sponsored slot. It cannot buy a rating, a score, a ranking, a place in an award, or a different position in a list. Nobody can pay to be rated more highly, and nobody can pay to be left out. Any business meeting our published inclusion criteria is assessed on the same basis whether they pay us, ignore us, or dislike the result.
Why we draw the line there. The moment a score can be bought, every other number on this site becomes worth less. The data below is only useful to you if it isn't for sale, and the same has to be true of any judgement we publish.
What we don't do. We don't make personal recommendations — we're a referrer, not a licensed adviser, so we show options to explore rather than telling you what to choose. We don't publish a rating without publishing the formula behind it. And we don't invent data: every figure is either real and cited, or clearly labelled as modelled.
canweaffordit.com.au is an independent website. We are not affiliated with the Australian Government, Domain, REA Group, or any lender.
We may receive a referral fee when you connect with a broker, agent, or service partner through this site. This does not influence our data, calculations, ratings or rankings.
Questions about our data? Contact us.