CGT Calculator Australia: Calculate Capital Gains Tax on Shares
Calculate capital gains tax on Australian shares, ETFs and other assets in seconds. This free capital gains tax calculator applies the 50% CGT discount for assets held over 12 months, your marginal tax rate, and the legislated July 2027 changes (inflation indexing + 30% minimum). No sign-up required.
What this calculator covers: listed investments such as shares and ETFs, and investment property that has always been rented or vacant. It assumes the asset is subject to the 2027 rules. It does not model the main residence exemption (your home is generally CGT-free), the 6-year rule, inherited property, negative gearing, the affordable-housing 60% discount, or foreign-resident withholding — where those apply, the calculator tells you so instead of estimating. If you are unsure whether an exemption applies, consult a registered tax agent.
How to calculate CGT in Australia
Capital Gains Tax (CGT) is not a separate tax — it forms part of your assessable income in the year you sell an asset. The tax you pay depends on your marginal income tax rate and how long you held the asset.
- Start with your sale proceeds and subtract the cost base (purchase price plus brokerage and other incidental costs).
- Deduct any capital losses from the same year or carried forward from earlier years.
- If you are an Australian resident individual and held the asset for more than 12 months, apply the 50% CGT discount.
- Add the remaining net capital gain to your taxable income – it is taxed at your marginal rate.
Current rules (until 30 June 2027)
- Held less than 12 months: the full capital gain is added to your taxable income.
- Held 12 months or more: you get a 50% discount — only half the capital gain is taxable.
New rules from 1 July 2027 (now law)
From 1 July 2027 the 50% discount is replaced by cost base indexation, and a 30% minimum tax rate applies to net capital gains. The reform received royal assent on 26 June 2026. See what changes in 2027 below.
Want to model your entire portfolio? Crowdfolio tracks all your lots and generates CGT-aware rebalancing recommendations automatically →
What is the CGT discount?
The CGT discount reduces the portion of a capital gain that is taxable when you have held an asset for at least 12 months. For the 2026–27 financial year it is still 50% for individuals and trusts, 33⅓% for complying superannuation funds, and nil for companies. The 12-month clock runs from the day after you acquire the asset to the day you enter the contract to sell it — not the settlement date.
Worked example: you buy $10,000 of ASX shares, sell them 14 months later for $18,000, and pay $40 brokerage on each leg. Your cost base is $10,040, your capital proceeds are $17,960, and your gross capital gain is $7,920. Because you held for more than 12 months, the 50% discount applies and $3,960 is added to your taxable income. On a 30% marginal rate that is $1,188 of tax, plus the 2% Medicare levy.
Sell the same parcel at 11 months instead and the full $7,920 is assessable — the single most expensive week in retail investing. The calculator above applies this test automatically once you enter your purchase and sale dates.
The 50% discount is being replaced from 1 July 2027. See what changes in 2027 below.
How the cost base works
Your cost base is what you paid for the asset plus the costs of acquiring, holding and disposing of it. Getting it right is where most CGT estimates go wrong — understating the cost base means overstating the gain and overpaying tax. The ATO recognises five elements:
- Acquisition cost — what you paid for the asset, or its market value if you did not acquire it at arm’s length.
- Incidental costs — brokerage on both the buy and the sell, stamp duty, legal fees, conveyancing, valuation and advice fees directly related to the transaction.
- Ownership costs — rates, land tax, insurance and interest on money borrowed to acquire the asset. These count only where you have not already claimed them as a tax deduction, which rules them out for most negatively geared property and for shares held on margin.
- Capital improvements — a renovation, extension or structural addition. Ordinary repairs and maintenance are deductible expenses, not cost base additions.
- Costs of preserving or defending your title to the asset.
For shares and ETFs the practical list is short: purchase price, buy brokerage, sell brokerage. For property it is long, and the difference is usually tens of thousands of dollars. Keep records for five years after the year you dispose of the asset.
Adjusted cost base and indexation
An adjusted cost base is simply the cost base after events that change it — a return of capital, a share split, a demerger, or an AMIT cost base adjustment from an ETF distribution. ETF investors are caught by this most often: the annual AMIT statement frequently reduces your cost base, which increases your eventual gain.
Cost base indexation is a separate mechanism that lifts the cost base in line with inflation so you are taxed on the real gain rather than the inflationary one. It currently applies only to assets acquired before 11:45am on 21 September 1999, and is frozen at the September 1999 CPI. If you hold such an asset you may choose either indexation or the 50% discount — whichever produces the lower gain. From 1 July 2027 indexation becomes the general method for individuals and trusts.
CGT changes from 1 July 2027
The reform is law. The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 passed the Senate on 25 June 2026 and received royal assent on 26 June 2026. It is no longer a proposal, and it applies to gains arising after 1 July 2027 regardless of when you bought the asset.
Three things change for Australian resident individuals and trusts:
- The 50% discount is replaced by cost base indexation. Instead of halving the gain, your cost base is lifted by inflation and you are taxed on the real gain. The 12-month holding rule still applies.
- A 30% minimum tax rate applies to net capital gains. If your marginal rate would produce a lower effective rate on the gain, the 30% floor applies instead.
- There is a deemed disposal and reacquisition on 1 July 2027. Every CGT asset is treated as sold and rebought at market value that day. The notional gain up to that point is deferred — you are not taxed in 2027 — and when you eventually sell, that pre-2027 slice may still receive the 50% discount, while growth after 1 July 2027 is indexed.
That transitional split matters more than the headline. An investor who has held ASX shares since 2015 does not lose the 50% discount on the gain already accrued — only on future growth.
Assets acquired before 20 September 1985 are also captured: they take a cost base of their market value at 1 July 2027, so pre-CGT assets cease to exist from that date.
Who is outside the Indexation Reform: companies, superannuation funds, life insurance companies, and foreign or temporary residents. Owners of new residential dwellings and affordable housing may elect to keep the 50% discount instead.
Separately, residential dwellings acquired after 7:30pm AEST on 12 May 2026 lose negative gearing treatment from 1 July 2027, with net rental losses quarantined against residential rental income. New dwellings and dwellings acquired before that date are unaffected.
Still announced but not legislated: the Innovative Business CGT Concession for founders and early-stage investors, temporary rollover relief, and the 30% minimum tax on discretionary trust distributions flagged for 1 July 2028.
Full detail: what the 2027 CGT changes mean for investors.
Does capital gains tax differ by state?
No. Capital gains tax is federal. It is imposed under the Income Tax Assessment Act and administered by the ATO, so the rate and the rules are identical whether you live in New South Wales, Queensland, Victoria, Western Australia, South Australia, Tasmania, the ACT or the Northern Territory. There is no state CGT, and searches for a “CGT calculator NSW” or “capital gains tax calculator QLD” are answered by the same national calculation.
What does vary by state is stamp duty and land tax on property. Those are state taxes, and stamp duty paid on acquisition is an incidental cost that forms part of your cost base — which is the one place your state genuinely changes the CGT answer. Land tax counts only if you have not claimed it as a deduction.
Your marginal tax rate is also national. For 2026–27 the resident rates are 0% up to $18,200, 15% to $45,000, 30% to $135,000, 37% to $190,000 and 45% above that, plus the 2% Medicare levy.
This calculator produces an estimate for general information only and is not personal financial or tax advice. Confirm your position with the ATO or a registered tax agent.
Frequently asked questions
Does this calculator account for FIFO or specific parcel selection?
This calculator uses a single average cost per unit. For full FIFO, LIFO, or specific parcel selection across multiple parcels, use Crowdfolio — it tracks each lot separately and chooses the method that minimises your CGT.
Can I use this for shares in an SMSF?
An SMSF in accumulation cops a flat 15% on capital gains, dropping to 7.5% once the 12-month discount kicks in. Pension phase? Generally zero. Plug in 0.15 for modelling, or ask your auditor; they’re paid to worry about this stuff.
How do you calculate CGT?
Subtract your cost base (what you paid for the asset, including brokerage and other incidental costs) from your sale proceeds to get your capital gain. Deduct any capital losses, then apply the 50% CGT discount if you are an Australian resident individual and held the asset for more than 12 months. The remaining net gain is added to your taxable income. The full method is on the ATO’s calculating your CGT page.
How is CGT calculated on shares?
Each parcel of shares is worked out separately: sale proceeds minus the cost base (purchase price plus brokerage). Parcels held for more than 12 months qualify for the 50% discount, while parcels sold within 12 months are taxed on the full gain. Which parcels you sell can therefore change the tax outcome, which is why lot-level tracking matters.
How much is capital gains tax in Australia?
There is no separate CGT rate in Australia. Your net capital gain is added to your taxable income and taxed at your marginal income tax rate (up to 45%, plus the Medicare levy). If the asset was held for more than 12 months, the 50% discount halves the taxable gain, making the effective top rate on that gain 22.5% plus the Medicare levy.
What is the CGT discount?
The CGT discount reduces a capital gain by 50% for Australian resident individuals who have held an asset for at least 12 months before selling. Complying super funds receive a 33.33% discount and companies receive none. Eligibility rules are on the ATO’s CGT discount page.
How is CGT calculated on property?
Subtract the cost base from the sale proceeds. For property the cost base includes the purchase price, stamp duty, legal and conveyancing fees, buyer’s agent fees, and capital improvements such as a renovation or extension — but not repairs, and not rates, insurance or interest you have already claimed as deductions. Deduct any capital losses, then apply the 50% discount if you held the property for more than 12 months. Your main residence is generally exempt, and the six-year rule can preserve that exemption for up to six years after you move out if the property is rented.
Is there a different capital gains tax calculator for NSW, QLD or Victoria?
No. Capital gains tax is a federal tax administered by the ATO, so the calculation is the same in every state and territory. The only state-specific input is stamp duty on property, which forms part of your cost base and therefore reduces your taxable gain.
Have the 2027 CGT changes passed into law?
Yes. The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 passed the Senate on 25 June 2026 and received royal assent on 26 June 2026. From 1 July 2027 the 50% CGT discount is replaced by cost base indexation for Australian resident individuals and trusts, and a 30% minimum tax rate applies to net capital gains. A deemed disposal on 1 July 2027 preserves the 50% discount on gains accrued before that date. Some related measures — the Innovative Business CGT Concession, temporary rollover relief, and the proposed 30% minimum tax on discretionary trust distributions from 2028 — have been announced but are not yet law.
What is an adjusted cost base?
An adjusted cost base is your original cost base after events that change it — a return of capital, a share split, a demerger, or an AMIT cost base adjustment from an ETF distribution. ETF investors are affected most often, because the annual AMIT statement commonly reduces the cost base and therefore increases the eventual capital gain.