Free tool
CGT calculator for Australian property — built for the 1 July 2027 reset.
Most CGT calculators ignore the elephant in the room: from 1 July 2027 the 50% discount is replaced by cost-base indexation plus a 30% minimum effective rate, and property held across the reset date gets taxed under a transitional regime. This calculator models that reform, and shows you the gap between the two apportionment methods the ATO accepts.
+How to use this calculator
- Enter your scenario — purchase date and price, sale date and price (actual or projected), and the costs each side. Hover the icons next to each label for guidance on what to include.
- Pick your tax position — the income bracket reflects 2024-25 ATO resident rates after the revised Stage 3 cuts, plus 2% Medicare levy.
- Add a 1 July 2027 value (optional, but recommended) — this is where the calculator shows you what a contemporaneous Landmark valuation is worth in tax-saved dollars. Leave it blank and you'll see only the Treasury-default apportionment formula.
- Read both columns — the right-hand panel shows the tax under Treasury's specified apportionment formula vs a market valuation. The gap is the upside a 1 July 2027 valuation captures.
The figures are indicative — see the disclaimer at the bottom for the full list of what's excluded.
Methodology
How the calculator works.
Treasury's Budget 2026-27 factsheet (page 4) expressly allows taxpayers to determine an asset's value at 1 July 2027 by either of two methods. The calculator implements both and shows the difference.
Time apportionment formula
Treasury's “specified apportionment formula” (the ATO has committed to publishing a tool). Days held before 1 July 2027 divided by total holding days gives the pre-reset fraction; the post-reset fraction is the remainder. The total gain is split on that pro-rata basis based on the asset's overall holding- period growth rate.
Simple, requires no extra evidence, and is the default fallback. It is materially less accurate whenever the market moved non-linearly across the reset — which is virtually always. Sydney apartments, regional QLD acreage, mining-town industrial: each has its own market trajectory the pro-rata formula doesn't see.
Contemporaneous market valuation
Treasury's first-named method: “seek a valuation of the asset as at 1 July 2027”. Prepared by a RICS-Registered Chartered Valuation Surveyor at or near the reset date. The pre-reset gain becomes (2027 value − original cost base); the post-reset gain becomes (sale proceeds − 2027 value). Each portion is taxed under its own regime.
More accurate, more defensible if the ATO queries the apportionment on audit, and — depending on how the market moved across your specific reset window — usually results in a lower total CGT bill than the apportionment formula. Read the full CGT valuation overview or the pillar guide on retrospective valuation methodology.
Sources
Where the numbers come from.
Tax law is YMYL content. Every claim on this page is anchored to a primary source — Treasury, ATO, or the Income Tax Assessment Act 1997. Verify with your accountant before acting on any figure.
- Treasury — Negative Gearing and Capital Gains Tax Reform factsheet (PDF, Budget 2026-27)
Primary source for the reform package. Pages 3-4 cover the transitional arrangements, the two apportionment methods, the 30% minimum tax mechanic, new-build choice, affordable-housing 60% retention, and the means-tested low-income exemption. Pages 7-8 contain the official worked cameos (Michael, Zoe, Jane) that this calculator aligns with.
- ATO — Tax reform: boosting home ownership, reforming negative gearing and CGT
ATO landing page tracking the reform. As of today the ATO describes the reform as “not yet law” and is preparing the apportionment-formula tool referenced in Treasury's factsheet.
- ATO — Resident individual income tax rates (2024-25)
Source of the four marginal brackets used in the calculator dropdown (16% / 30% / 37% / 45% before the 2% Medicare levy), reflecting the revised Stage 3 cuts effective 1 July 2024.
- Budget 2026-27 — Tax reform chapter
Context for the package: the Government's stated rationale (housing affordability, intergenerational fairness), the OECD recommendations cited, and the housing-supply impact modelling.
- realestate.com.au — Investors warned: get a valuation now or pay more tax
Mainstream-media framing of the reform from a property investor angle. Quantifies a representative sensitivity (“the difference between a defensible $1,050,000 valuation and an under-cooked $950,000 valuation could easily exceed $30,000 in extra tax”) — the same leverage the “Sensitivity” band in this calculator surfaces dynamically.
Frequently asked
Calculator questions.
What is the 1 July 2027 CGT reform, and is it legislated yet?+
The 2026-27 Federal Budget (announced 12 May 2026) proposes that, from 1 July 2027, the long-standing 50% CGT discount be replaced by CPI-based cost-base indexation, and a minimum 30% effective tax rate be introduced — applied as a floor on the marginal-rate calculation for the post-2027 portion of any gain. Property held across the reset date is taxed under a transitional regime that apportions the gain between the pre-2027 portion (existing 50% discount rules) and the post-2027 portion (new indexation + 30% floor). As of today, no bill has been introduced into Parliament; the changes are subject to passage of legislation. See the Treasury factsheet at budget.gov.au for the official package detail.
Why does the calculator show two different tax outcomes?+
The Treasury factsheet (12 May 2026) explicitly offers taxpayers two methods to determine the asset's value at 1 July 2027 when the asset is later realised: (a) seek a contemporaneous market valuation of the asset as at 1 July 2027, or (b) use a specified apportionment formula that estimates the value based on the asset's growth rate over its holding period (the ATO has committed to publish a tool for this). The calculator shows both side-by-side so you can see the gap, which is exactly what a market valuation captures when prices moved non-linearly across the reset.
Do I need a professional valuation, or is the calculator enough?+
The calculator is indicative only — useful for planning conversations with your accountant. The Treasury factsheet expressly allows either a valuation or the ATO apportionment formula. An independent market valuation prepared by a RICS-Registered Chartered Valuation Surveyor is the most defensible position if the figure may later be queried on audit, particularly where the market moved sharply across the reset date. The calculator's output is not a substitute for that report.
What does the calculator exclude?+
The calculator excludes: main residence exemption (which remains exempt for CGT purposes), the four small-business CGT concessions (unchanged), the existing 60% CGT discount for qualifying affordable housing (fully retained under the reform), the new-build choice between the 50% discount and the new indexation rules, superannuation funds including SMSFs (which are excluded from the reform entirely per Treasury page 1), depreciation clawback, carried-forward losses, trust and company structures, foreign tax offsets, and the means-tested low-income exemption from the 30% minimum tax (Age Pension and JobSeeker recipients — see below). It assumes you are an Australian tax resident individual selling a single investment property.
Where do the tax brackets come from?+
The four income brackets in the dropdown are the 2024-25 Australian Taxation Office resident individual rates (after the revised Stage 3 tax cuts that took effect 1 July 2024), with the 2% Medicare levy added to the top of each. The brackets are: under $45,000 (18% effective), $45,001 to $135,000 (32%), $135,001 to $190,000 (39%), and over $190,000 (47%). Treasury's CGT cameos use 32% and 47% as the reference marginal rates. The 30% minimum CGT rate from 1 July 2027 applies on top of these as a floor on the post-2027 portion.
What if my marginal rate is below 30%?+
For the post-1 July 2027 portion of your gain, the calculator applies the higher of your marginal rate or the 30% minimum effective rate. For the pre-2027 portion, your marginal rate applies after the 50% discount as it does today. The Budget proposal expressly exempts recipients of means-tested income support payments (such as the Age Pension or JobSeeker) from the minimum tax for any financial year in which they receive a payment — the calculator currently doesn't model this exemption, so if it applies to you, your real-world tax may be lower than the figure shown.
What about new builds?+
Treasury proposes that investors in eligible new builds — residential properties that genuinely add to housing supply, such as dwellings on previously vacant land or knock-down rebuilds that increase the dwelling count — can choose either the existing 50% CGT discount or the new indexation+30% minimum arrangements when they sell. The choice is per-property and subsequent purchasers do not inherit the option. The calculator currently models the standard transitional regime; if you own an eligible new build, run both scenarios manually by including or omitting the 1 July 2027 value to compare which choice produces the lower tax for your situation.
Related
Continue reading.
- Capital Gains Tax Property ValuationThe flagship service page — what we deliver, when you need it, and how the report is structured.→
- Where the apportionment formula leaves investors exposedEditorial response to the realestate.com.au investor warning — regional markets, improved properties, multi-asset portfolios.→
- Retrospective valuation for CGT cost baseMethodology pillar — historical sales, archival evidence, 6 ATO acceptance scenarios.→
- Preparing for the 1 July 2027 CGT resetWorkflow companion — when to commission the valuation, what to capture, accountant coordination.→