Updated for the May 2026 reform
Capital Gains Tax Calculator ACT
CGT is federal - ACT sellers face the same enacted 2026 rules as the 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 ACT quirk runs the other way to every state: because Canberra property sits on 99-year Crown leases, conveyance duty is typically deducted in the purchase year rather than added to the cost base - so this page's auto costs exclude it.
- 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)
split at 1 Jul 2027*$54,867
- Capital gain (proceeds − adjusted cost base)
- $366,150
- Banked to 1 Jul 2027 (50% discount treatment)
- $30,822
- Accrued after 1 Jul 2027 (CPI-indexed)
- $115,477
- Taxable gain after discount/indexation/exemption
- $130,888
- Net proceeds after CGT
- $1,163,883
The same sale under each regime
Grandfathered
$54,867
split at 1 Jul 2027
Established (post-reform)
$54,867
split at 1 Jul 2027
New build
$79,395
50% discount
If CPI runs low or high - the 2-3% band
CPI 2%/yr
$77,193
+$22,326 vs assumed
CPI 2.5%/yr - assumed
$54,867
the headline figure
CPI 3%/yr
$31,653
−$23,214 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 ACT costs inside this estimate
- Investor transfer duty at $850,000
- $28,100
- Conveyancing (default)
- $2,000
- Building and pest (default)
- $600
- Selling costs (default 2.5% of sale)
- $31,250
Shown for reference, not added to the cost base: ACT investment properties are 99-year Crown leases, and the ATO accepts conveyance duty on them as deductible in the year it is paid rather than as a cost base item. If you did not claim the deduction, add the duty to the purchase costs field - and confirm the treatment with your accountant.
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 the Australian Capital Territory: federal tax, ACT numbers
The ACT is the one jurisdiction where the usual state chapter of a CGT story runs backwards. Everywhere else, stamp duty's consolation prize is the cost base - not deductible now, but shrinking the gain at sale. In Canberra the prize comes early: because every residential block sits on a 99-year Crown lease, the ATO accepts conveyance duty on an investment purchase as deductible in the year it is paid. That is worth more than the cost base route on any time value of money - and it is why this page, unlike its state siblings, leaves duty out of the auto purchase costs and shows it for reference instead. If you did not claim it, add it back and the engine treats it like any other acquisition cost.
From there the federal machinery is identical - the ATO treats the Crown lease as ownership, and the audited national engine runs unchanged. The gain splits at the 1 July 2027 deemed sale: the earlier slice keeps 50% discount treatment, later gains are CPI-indexed with the 30% minimum tax, and first-owner new builds keep the discount beyond the split. ACT land tax - from the first dollar of AUV on any home that is not your residence - was deductible along the way and never appears here, though for established purchases contracted after 12 May 2026 the losses it deepened feed the quarantined pool applied at sale. The territory that pioneered taxing property annually instead of at transfer turns out to have pioneered the cleaner CGT sum too.
The ACT stamp duty calculator prices the duty this page shows for reference on the way in. While you hold, ACT land tax applies from the first dollar of AUV on any residence that is not your home - a fixed charge plus a valuation charge, billed quarterly - deductible against rent and never part of the cost base. And if the property was ever your home first, the ACT first home buyer calculator prices the uncapped Home Buyer Concession Scheme that may have applied - and 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 ACT 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 the ACT?
Under the same federal rules as the states - the ATO treats a 99-year Crown lease as ownership for CGT. Sale proceeds after selling costs, minus the cost base: purchase price plus legals and inspections, less Division 43 capital works claimed. The enacted 2026 reform splits the gain at 1 July 2027: the earlier slice keeps the 50% discount, later gains use CPI indexation plus a 30% minimum tax, taxed at your marginal rate. The ACT difference is duty - typically deducted in year one, not in the cost base.
Why is ACT stamp duty not in my cost base?
Because Canberra property is leasehold - every residential block sits on a 99-year Crown lease. The ATO accepts that conveyance duty on an ACT investment property is deductible in the year it is paid, as a cost of acquiring a lease used to produce income, rather than forming part of the CGT cost base as it does in every state. The benefit arrives decades earlier - a deduction at your marginal rate now instead of a smaller gain later. This calculator's auto purchase costs therefore exclude duty; add it back if you did not claim the deduction.
Does ACT land tax reduce the capital gain?
No. ACT land tax - which applies from the first dollar of average unimproved value on any residence that is not the owner's principal place of residence, as a fixed charge ($1,778 for 2026-27) plus a valuation charge billed quarterly - is deductible against rent each year and never enters the cost base. For established-class purchases contracted after 12 May 2026, land tax that deepens a rental loss feeds the quarantined pool this calculator applies at sale.
Does the main residence exemption work on a leasehold Canberra home?
Yes - identically to freehold. The ATO treats the Crown lease as ownership, so the main residence exemption covers the years the property was your home, and the 6-year absence rule can extend it after you move out and rent it, provided you claim no other main residence in that window. Enter the years lived in first and this calculator apportions the exemption across the hold.
What did the May 2026 reform change for ACT sellers?
For gains accruing from 1 July 2027 the 50% discount is replaced by CPI indexation plus a 30% minimum tax - for every owner in every jurisdiction, the ACT included. The gain to that date is banked under the old discount rules via a deemed sale. First-owner new builds keep the 50% discount for later gains with a per-sale option to elect indexation - relevant in a territory where infill development is steady. This calculator uses a labelled 2.5% a year CPI proxy.