The calculator
From 1 July 2027 the 50 per cent discount goes. In its place: indexation and a 30 per cent minimum tax on the gain. Enter what you paid and what you sell for. It shows you the bill today, the bill under the new rules, and the gap.
Your gain: $0
Tax today
Tax from 1 July 2027
After-tax return, today's rules
After-tax return, new rules
| Inflation p.a. | Keep, today's rules | Keep, new rules | Difference |
|---|
Higher inflation means a bigger indexation allowance under the new rules, so the gap narrows. Below about 4 per cent, on most inputs, you pay more.
How we worked it out
The mechanics follow the Treasury Laws Amendment (Tax Reform No. 1) Act 2026 and its Explanatory Memorandum. From 1 July 2027 the 50 per cent discount for individuals and trusts is replaced by cost base indexation on gains that accrue from that date, for assets held at least twelve months, with a 30 per cent minimum tax on the real gain. An asset held across 1 July 2027 is split: the gain to that date keeps the discount, the gain after it is indexed and floored. The Act lets you use the market value at 1 July 2027 or the apportioning method in the Income Tax Assessment (Method for Apportioning Capital Gains and Capital Losses) Determination 2026. The automatic method here is that Determination: a daily growth rate from what you paid to what you sell for, applied to the days you held the asset before 1 July 2027, gives the deemed value on that date. That value becomes the cost base for indexation. If you know the market value, enter it instead. New residential dwellings keep a choice of the discount, so we show no change for them.
Simplifications: your income bracket stands in for a typical income inside it ($30,000, $80,000, $160,000 or $250,000) and the gain is taxed on top of it; inflation is a flat assumption you can change; the same resident rate scale, the one in force in the year you sell, is used for both figures so the gap shows the rule change only; the Medicare levy is a flat 2 per cent; small business CGT concessions, the income support exemption and state taxes are not modelled. This is an estimate to show the direction and size of the change. It is not tax advice. Get your own.
Your MP is counting on you not noticing. Thirty seconds and a postcode tells them you do.