How to use this calculator: Enter your purchase price, expected sale price, how long you've held (or plan to hold) the asset, the average annual CPI over that period, and your income tax bracket. The calculator shows your CGT under the old 50% discount versus the new indexation model that applies from 1 July 2027 — so you can see which is better for your situation.
Applies to: investment properties, shares, ETFs, and other CGT assets held by individuals outside super. New residential builds can choose whichever model is lower.
Must be at least 1 year to qualify for any CGT discount
RBA target is 2–3%. Use higher values for longer historical periods.
Medicare levy (2%) is included in the calculation automatically
New builds can choose whichever method gives a lower tax bill
Old 50% Discount
tax payable
New Indexation Model
tax payable
Show full breakdown
| Item | Old (50% discount) | New (Indexation) |
|---|
This calculator provides general estimates only and does not constitute tax advice. Actual CGT depends on your individual circumstances, including cost base adjustments, capital losses carried forward, and income in the year of sale. Consult a registered tax agent before making investment decisions. The new indexation rules apply to assets purchased after 7:30pm AEST 12 May 2026 and take effect from 1 July 2027.
How the Two Models Compare
Old model (50% discount): You pay tax on half your nominal capital gain, at your marginal rate. Simple, predictable — but the benefit scales with the size of the gain, not with inflation.
New model (CPI indexation): Your purchase price is adjusted upward by cumulative CPI. You only pay tax on the gain above that inflation-adjusted cost base. In high-inflation environments this is better. In high-growth, low-inflation environments (most of Australian property history) it produces a higher tax bill.
30% minimum tax floor: If your marginal rate in the year of sale would otherwise be below 30%, the new rules apply a 30% floor on CGT. For most investors in the 37% or 45% bracket, the marginal rate always applies — the floor only bites for lower-income earners.
New builds: Investors in new residential builds can choose either model at the time of sale — whichever produces the lower tax bill. This is a permanent advantage over existing property purchases from 1 July 2027.
For the full budget announcement and what it means for your investment strategy, read our article: 2026 Budget: Negative Gearing and CGT Overhauled.
Calculator built by Amit Narang, Mortgage Broker | Credit Representative 558902 of Outsource Financial Pty Ltd (ACL 384324). General information only — not tax advice.
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