Free tool · 2027 tax rules built in
Property growth calculator
Three numbers in, full breakdown out. Parliament rewrote the rules for investors on 25 June 2026, and the same house now has two very different tax outcomes depending on whether it's a new build or established stock. This shows you both, to the dollar.
Everything else is pre-filled with honest defaults: 20% deposit, 6.5% interest only, 39% tax bracket, growth at the 6.4% national 30 year average, 10 year hold. You can change all of it after.
A worked example, for the skimmers: on the default numbers ($750,000 purchase, $550 a week rent, 39% bracket, 6.4% growth) the new build path costs about $113 a week after tax in year one against $296 established, breaks even on cash flow in year 6 versus year 9, and finishes about $78,890 ahead over 10 years. Your numbers will differ. That's what the button is for.
Run the numbers first.
$0
Value in 10 years
$0
New build, cost per week
$0
Established, cost per week
$0
The gap after 10 years
Net position if you sold · after tax
Everything in: cash flow, tax, and CGT if you sold at the end of each year. The gap between the lines is what the new rules cost an established buyer.
The full breakdown
| New build | Established | |
|---|---|---|
| Year one, holding it | ||
| Rent collected | ||
| Loan interest | ||
| Running costs | ||
| Depreciation claimed | ||
| Tax back, year one | ||
| True cost per week | ||
| Cash flow break-even | ||
| Selling in year 10 | ||
| Sale price | ||
| Tax back over the hold | ||
| Carried-forward losses used | ||
| CGT method | ||
| CGT bill | ||
| Net result, after tax | ||
Modelled at the 6.4% national average (CoreLogic, 30 years). Your suburb will sit above or below that, and the gap is the whole game. I can email you where it actually sits.
Adjust the assumptions
One honest caveat. The calculator gives both paths the same growth rate, and in the real world they rarely get it. A new build usually means more building and less land for the money, and land is the part that grows. Whether the tax saving beats the land you gave up is a suburb-by-suburb question, not a slider.
This models the hold-and-sell. For the week-to-week reality, rent in, every cost out, use the cash flow calculator.
What actually changed
The rules, in plain English.
Negative gearing
Buy established after 7:30pm on 12 May 2026 and from 1 July 2027 your rental losses stop offsetting your salary. They queue up instead, waiting for rental profits or your eventual sale. New builds keep negative gearing exactly as it was.
Capital gains
The 50% CGT discount is replaced with cost-base indexation and a 30% minimum rate on gains for established stock. New builds get to choose whichever method taxes less. Anything held before budget night keeps the old rules.
What counts as new
House and land, off the plan, townhouses, developments that add dwellings to a site. Not renovations, not one-for-one knockdown rebuilds, and not granny flats on an established block. Yes, that last one matters to us. A granny flat still lives or dies on rent versus build cost, which is what the feasibility analyser checks.
The long version, including the three caveats before anyone rushes out and buys a house and land package, is written up in the plain-English guide to the 2026 changes.
Free · Put together by hand
Want the full suburb breakdown?
The calculator uses the national average because that's the honest thing to do without suburb data. The full breakdown is the real thing: 10 years of growth for the suburb, vacancy, days on market, rents, and the supply coming down the pipe. I pull it together and email it through. No charge, and no 14-part email sequence after it.
Fair questions
The fine print, asked properly.
When do the new investor tax rules actually start?
The package passed parliament on 25 June 2026, but the cutoff was budget night: 7:30pm on 12 May 2026. Buy an established property after that date and from 1 July 2027 your rental losses are quarantined and the 50% CGT discount is replaced with cost-base indexation and a 30% minimum rate. Properties held or under contract before the cutoff keep the old rules.
What happens to negative gearing if I buy an established house now?
You can still deduct rental losses against your salary until 30 June 2027. After that the losses don’t disappear, they queue up. They carry forward and can only offset rental profits or the capital gain when you eventually sell. New builds keep negative gearing as it was.
Does a granny flat count as a new build?
No. A granny flat on an established block sits outside the new build definition, so it doesn’t buy back negative gearing. It still stacks up or doesn’t on rent versus build cost, which is exactly what our free feasibility analyser checks.
How do I calculate capital growth on a property?
Future value = purchase price × (1 + growth rate) ^ years. A $750,000 house at 6.4% a year is about $1.39 million after 10 years. The calculator above does the compounding for you, then layers the tax rules on top, because growth is only half the answer. What you keep after tax is the number that matters.
Is this calculator financial advice?
No. It’s general modelling with deliberately simple assumptions, built so you can see the shape of the new rules on real numbers. Your bracket, structure and loan will move the result. Run anything serious past your accountant before acting on it.
General information only, not tax, financial or credit advice. The modelling is deliberately simple: interest-only loan, flat interest rate, costs rising at 2.5%, and it ignores stamp duty, buying and selling costs, land tax, vacancy and the part-year of negative gearing available before 1 July 2027. Rules as legislated 25 June 2026, and they can change again. Get advice on your own situation before acting.
Numbers look interesting?
The calculator is the easy 10%. Which suburb, which street and which contract clause is the other 90%. That's a call, not a slider.