Updated for the May 2026 reform
Capital Gains Tax Calculator WA
CGT is federal - WA sellers face the same enacted 2026 rules as the eastern states: the gain splits at 1 July 2027, the earlier slice keeps the 50% discount, later gains use CPI indexation plus a 30% minimum tax. The WA layer is the cost base: on a $750,000 purchase this page starts you with $29,741 of RevenueWA transfer duty inside it, reducing the taxable gain at sale.
- Rates verified
- 2026-08-03
- Reform
- Split at 1 Jul 2027
- Classes
- All three
The sale
= sold in FY ending 2036
CGT payable - Established (post-reform)
CPI indexation*$38,576
- Capital gain (proceeds − adjusted cost base)
- $290,160
- Taxable gain after discount/indexation/exemption
- $96,225
- Net proceeds after CGT
- $1,033,924
The same sale under each regime
Grandfathered
$38,576
CPI indexation
Established (post-reform)
$38,576
CPI indexation
New build
$61,537
50% discount
If CPI runs low or high - the 2-3% band
CPI 2%/yr
$58,270
+$19,694 vs assumed
CPI 2.5%/yr - assumed
$38,576
the headline figure
CPI 3%/yr
$19,486
−$19,090 vs assumed
The enacted law indexes the reset cost base by actual CPI, which no one can know in advance. Higher inflation indexes the cost base harder and lowers the taxed gain; lower inflation does the opposite. The band shown is the RBA inflation target the 2.5%/yr assumption is the midpoint of (source).
The WA costs inside this estimate
- Investor transfer duty at $750,000
- $29,741
- Conveyancing (default)
- $2,000
- Building and pest (default)
- $600
- Selling costs (default 2.5% of sale)
- $27,500
WA transfer duty on an investment purchase is not deductible while you hold - it joins the cost base and comes off the gain at sale. Auto-estimated from the RevenueWA general scale at the purchase price; override with your contract figures.
CGT is the last chapter of a deal. The full audit runs it against everything that came before - acquisition costs, cash flow and the quarantined loss pool it absorbs.
Deal Auditor - in build, not yet available
*The enacted law indexes cost bases by actual CPI; future CPI is unknowable, so this calculator assumes a 2.5%/yr CPI proxy (the middle of the RBA target band). The 1 Jul 2027 split defaults to a constant-growth interpolation unless you enter a valuation. Confirm the mechanics with your accountant (source). General information only.
CGT in Western Australia: federal tax, WA numbers
Western Australia's property market moves in cycles the east coast does not share - and under the enacted 2026 rules, timing against the 1 July 2027 split is where that matters most, because the split is by market value at a date. Gain accrued before the deemed sale that day is banked under the old 50% discount treatment; gain after it is CPI-indexed and carries the 30% minimum tax. A Perth hold that ran hard before 2027 and one that boomed after can produce very different tax on the same headline gain. CGT itself is federal - the WA layer is the cost base, and this page starts it with RevenueWA duty at your purchase price, plus standard defaults, all overridable.
The engine is the audited national one. Along the hold, WA's carrying costs - land tax above $300,000 of aggregated unimproved value on a scale unchanged since 2008-09, plus the 0.14% MRIT on Perth metropolitan land - were deductible against rent and never touch this sum, though for established purchases contracted after 12 May 2026 the losses they deepened feed the quarantined pool applied here at sale. If you hold a 1 July 2027 valuation, enter it: the default constant-growth interpolation smooths exactly the kind of cycle WA specialises in, and the statutory split is valuation-primary.
The WA stamp duty calculator prices the duty this page adds to your cost base on the way in. While you hold, WA land tax starts above $300,000 of aggregated unimproved value - a flat $300 to $420,000, then a scale unchanged since 2008-09 - deductible against rent each year and never part of the cost base. And if the property was ever your home first, the WA first home buyer calculator shows the first home owner rate (nil to $600,000 statewide) that may have applied - years lived in first feed the main residence exemption and the 6-year absence rule here. The national CGT calculator is this same engine without the WA defaults, and the negative gearing calculator projects the quarantined loss pool this page applies at sale.
Frequently asked questions
How is capital gains tax calculated on an investment property in WA?
Under the same federal rules as every state. Sale proceeds after selling costs, minus the cost base: purchase price plus buying costs such as RevenueWA transfer duty ($29,741 on a $750,000 purchase under the general scale) and legals, less any Division 43 capital works claimed. The enacted 2026 reform then splits the gain at 1 July 2027 - the earlier slice keeps the 50% discount, later gains use CPI indexation plus a 30% minimum tax - and the taxable amount is taxed at your marginal rate on top of income.
Is CGT different in Western Australia?
No - CGT is federal, and Perth's boom cycles are taxed by the same rules as Sydney's. The WA layer is the inputs: RevenueWA duty in the cost base, land tax above $300,000 of aggregated unimproved value (plus the 0.14% MRIT on Perth metropolitan land) as deductible holding costs, and WA's cycle timing deciding how much of your gain sits either side of the 1 July 2027 split.
How does the 1 July 2027 split interact with a WA price cycle?
Directly - the split is by value at a date, and WA's sharp cycles can load the gain on one side of it. The law deems every asset sold and re-acquired at its 1 July 2027 market value: gain accrued before that date is banked at 50% discount treatment, gain after it is CPI-indexed with the 30% minimum tax. A Perth property that ran hard into 2027 banks a big discounted slice; one that boomed later carries most of its gain under the new rules. Enter a 1 July 2027 valuation if you have one - otherwise this calculator interpolates at a constant growth rate, which smooths a cycle.
Does WA land tax or MRIT reduce the capital gain?
No. WA land tax - nothing to $300,000 of aggregated unimproved value, a flat $300 to $420,000, then a scale unchanged since 2008-09 - and the Metropolitan Region Improvement Tax of 0.14% on Perth metro land are both deductible holding costs, claimed against rent each year. Neither joins the cost base. For established-class purchases contracted after 12 May 2026, holding costs that deepen a rental loss feed the quarantined pool this calculator applies at sale.
What did the May 2026 reform change for WA sellers?
For gains accruing from 1 July 2027 the 50% discount is replaced by CPI indexation plus a 30% minimum tax, for every owner, grandfathered or not - the earlier gain is banked via the deemed sale at that date. First-owner new builds keep the 50% discount for later gains with a per-sale election for indexation instead. Future CPI is unknowable, so this calculator uses a labelled 2.5% a year proxy.