Enter what you paid and what you're selling for, your income and when the contract is signed. You'll see the capital gain, the part that's taxed, and the tax under today's rules or the rules that start on 1 July 2027.
How it adds up
What the calculator follows
Today’s rules are the ATO’s: the capital gain is what you receive less the cost base (ATO, how to calculate CGT), halved if you owned the property for at least 12 months as an Australian resident (ATO, CGT discount), and the result is added to your income and taxed at the 2026–27 resident rates plus the 2% Medicare levy. The CGT event is the contract date, not settlement.
For a contract from 1 July 2027 the calculator applies the Tax Reform No. 1 Act 2026, which the ATO describes as now law. The gain up to the 1 July 2027 value keeps the 50% discount. The gain after it isn’t discounted; instead the 1 July 2027 value is indexed by CPI, and a minimum tax ensures that newer gain bears at least 30%, which the calculator works the way the Budget explainer’s example does. It uses the 2027–28 rates, where the 15% bracket becomes 14%.
What it leaves out, so you can discount it. It doesn’t forecast CPI: the indexation factor starts at 1.000, which indexes nothing and overstates the newer gain. It doesn’t apply the main residence exemption or the 6-year rule, capital losses, rental losses quarantined under the new negative gearing rule, the new-build choice, or the minimum-tax exemption for people on listed Centrelink payments. One owner only. This is general information, not tax advice: your accountant should confirm the figure before you sign a contract.
For gains accruing from 1 July 2027. The Treasury Laws Amendment (Tax Reform No. 1) Act 2026 replaces the 50% discount with cost-base indexation and a 30% minimum tax for individuals, trusts and partnerships. Gains made before that date keep the discount, so most people selling after it will have both.
Which date counts, the contract or settlement?
The contract. The ATO says the CGT event happens on the date of the contract to sell, not at settlement. A contract signed in June 2027 falls under today's rules even if it settles in August.
How do I get the value at 1 July 2027?
A market valuation is the default. The law also allows an apportioning method set by the Minister, and Treasury consulted on a draft in August 2026, but at 11 October 2026 it hadn't been made. A valuation around that date is the safe course if you're holding.
Why is the indexation factor 1.000?
Because it depends on CPI figures that haven't been published yet. Indexation multiplies the 1 July 2027 value by the CPI for the quarter you sell divided by the CPI from that date. At 1.000 the calculator indexes nothing, which overstates the gain; put in the factor once the ABS figures exist.
Does this cover my own home?
No. Your main residence is generally exempt, and the main residence exemption is unchanged by the 2026 law. A home that was rented for part of the time, or that you've used the 6-year rule on, needs your accountant.