CGT Estimator — Australia 2025–26

How much CGT will you actually owe?

Australian capital gains tax is calculated on top of your income. If you held the asset for more than 12 months you get a 50% discount. Enter your numbers to see your exact liability before you sell.

The asset
Purchase price ($)
Sale price ($)
Other costs — brokerage, stamp duty ($)
Purchase date
Sale date
Your income
Annual income (before this sale)
Estimated CGT payable
—
Enter your asset details to calculate
Gain breakdown
Sale price—
Cost base—
Capital gain—
50% discount—
Taxable gain—
After-tax outcome
Gross proceeds—
CGT payable—
Net proceeds—
Hold period—
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This calculator uses 2025–26 Australian individual tax rates and the 50% CGT discount for assets held longer than 12 months. It does not account for the Medicare levy (2%), rental property depreciation, foreign income, trust distributions, or business assets. This is an estimate only — not financial or tax advice. Consult a registered tax agent before selling. J&A Marsh Investments Pty Ltd (trading as AlphaIQ) holds no AFSL. For official tax guidance see ato.gov.au.

How Australian capital gains tax works in 2025–26

Capital gains tax (CGT) in Australia is not a separate tax. When you sell an asset for more than you paid for it, the profit — your capital gain — is added to your taxable income for that financial year and taxed at your marginal income tax rate. The rate you pay depends on your total income including the gain.

The most important rule in Australian CGT is the 50% discount for assets held longer than 12 months. If you owned the asset for more than 365 days before selling, only half your capital gain is included in taxable income. The other half is completely ignored. This single rule can save tens of thousands of dollars on a significant asset sale.

The 2025–26 Australian tax brackets

What counts as the cost base?

Your cost base is not just the purchase price. It includes brokerage fees paid when you bought and sold, stamp duty (for property), legal costs related to the acquisition, and certain capital improvement costs for property. Maximising your cost base legally reduces your capital gain and therefore your tax bill.

Timing matters: The ATO taxes capital gains in the year the contract is signed, not when settlement occurs. If you sign a sale contract on 28 June, the gain is assessable in that financial year even if settlement happens in July. For large gains, consider whether delaying signing until 1 July defers the liability by 12 months.

Capital losses and how they work

Capital losses can only be offset against capital gains — not against ordinary income like your salary. If your losses exceed your gains in a financial year, the excess loss is carried forward indefinitely and can be used against future gains. Losses never expire. This makes strategic loss harvesting — selling assets with embedded losses in the same year as a large gain — a legitimate and powerful tax minimisation strategy.

Using AlphaIQ for ongoing CGT management

This calculator shows your liability for a single asset sale. AlphaIQ tracks CGT across your entire ASX portfolio — monitoring your cost base, hold periods, 50% discount eligibility, and optimal sell sequencing to minimise your total tax bill year after year. The rebalancer shows you which positions to sell first and which to hold until the 12-month threshold is reached.