How the calculator works
- Sold before 1 July 2027: profit = sale price − cost base. If you held the asset more than 12 months, half of it is taxable.
- Bought before and sold after 1 July 2027: the gain up to the 1 July 2027 value is halved; the gain after it is reduced by indexing that value to inflation.
- Bought after 1 July 2027: the whole cost base is indexed to inflation (if held more than 12 months) and only the real gain is taxed.
- Tax = tax on your income plus the taxable gain − tax on your income alone, topped up so the real gain since 1 July 2027 is taxed at least 30%.
Worked example
You earn $120,000. You bought shares in January 2020 for $100,000, they are worth $150,000 on 1 July 2027, and you sell them in July 2029 for $180,000. Inflation runs at 2.5% a year.
With the 50% discount: $40,000 of the $80,000 profit is taxable, so the tax is $14,550.
Under the 2027 rules: $25,000 (half the gain up to 1 July 2027) plus $22,401 (the gain after indexing $150,000 for two years) is taxable — $47,401 — so the tax is about $17,436, roughly $2,900 more.
The 2027 capital gains tax changes at a glance
| Until 30 June 2027 | From 1 July 2027 | |
|---|---|---|
| Held more than 12 months | 50% discount | Cost base indexed to inflation |
| Minimum tax | None | 30% on real gains (income-support recipients exempt) |
| Gain built up before 1 July 2027 | 50% discount | Still 50% discount |
| Eligible new builds | 50% discount | Choice of discount or indexation |
Source: Treasury Laws Amendment (Tax Reform No. 1) Bill 2026 — Bills Digest, Parliamentary Library · ATO resident tax rates
Frequently asked questions
When do the new capital gains tax rules start?
They apply to assets sold (by contract date) on or after 1 July 2027. Sales before then keep the 50% discount for assets held at least 12 months.
I bought before 1 July 2027 and will sell later. How is my gain taxed?
The asset is treated as sold and bought back on 1 July 2027. The gain up to that date keeps the 50% discount; the gain after it is reduced by indexing the 1 July 2027 value to inflation, and the 30% minimum tax can apply to it.
How is the value on 1 July 2027 worked out?
You can use a market valuation at 1 July 2027 or an apportionment method set by the Minister, which has not been published yet. If you leave the field blank, the calculator spreads your total growth evenly over the time you held the asset.
What is the 30% minimum tax?
From 1 July 2027, tax on real (inflation-adjusted) capital gains must be at least 30%. It mainly affects people whose taxable income is below about $45,000, such as retirees. Age Pension and other prescribed income-support recipients are exempt.
Do the changes apply to shares and ETFs, or only property?
All CGT assets held by Australian resident individuals, trusts and partnerships, including shares, ETFs and investment property. Companies and super funds are outside the new indexation rules.
What about new builds and my own home?
Investors in eligible new residential builds can choose the 50% discount instead of indexation and the minimum tax. Your main residence exemption is unchanged.
Can I include capital losses?
This calculator works out one sale. Capital losses reduce your gains before any discount; under the new rules indexation cannot create or increase a loss. Check how your losses apply with a tax agent.