Enter what you paid, what you sold for and what it cost you at each end, and this works out the gain and the tax on it.
The tax comes from the statutory rate scale rather than from a marginal rate multiplied by the gain, which matters when a gain spans several brackets.
Works out the capital gain on an asset from its cost base, applies losses and any discount you are entitled to, and computes the tax as the difference the gain makes to your assessment on the statutory scale.
Which set applies depends on the jurisdiction and the date you enter. Sources last checked 2026-08-30.
Commonwealth — Income tax
1 July 2024 to 30 June 2026
Income Tax Rates Act 1986 (Cth), Schedule 7 Part I — Resident taxpayers
Commonwealth — Income tax
1 July 2026 to 30 June 2027
Income Tax Rates Act 1986 (Cth), Schedule 7 Part I — Resident taxpayers
Commonwealth — Income tax
1 July 2027 onwards
Income Tax Rates Act 1986 (Cth), Schedule 7 Part I — Resident taxpayers
Commonwealth — Medicare levy
1 July 2026 onwards
Costs of acquiring it
Transfer duty, legal fees and other incidental costs of buying form part of the cost base. Leaving them out overstates the gain by their whole amount.
Capital improvements
Money spent improving the asset, as opposed to maintaining it. Repairs you have already deducted against rental income are not improvements and adding them here would claim the same expense twice.
Owned for at least 12 months
The discount is only available where an asset has been held long enough. This is a question you answer rather than one the calculator infers, because it depends on dates it is not given.
Discount to apply
The general discount for a resident individual is fifty per cent. It differs for superannuation funds, is unavailable to companies, and is reduced or unavailable for foreign and temporary residents — so it is entered rather than assumed.
Capital losses available
Losses from this year or carried forward from earlier ones. They are applied before the discount, which is the order that matters.
The tax figure is the difference between your assessment with the gain and without it. That is not the same as the gain times your marginal rate: a large gain pushes income through several brackets, and the shortcut overstates the tax at some incomes and understates it at others.
The effective rate — tax as a share of the whole gain — is usually well below the marginal rate, because the discount halves what is assessed. Seeing both is the clearest illustration of what the discount is worth.
Proceeds after selling costs and tax is the figure to plan around. It is what actually arrives, and it is materially below the sale price on almost every asset.
Every figure below is computed by the same calculator on this page, from the inputs described. Nothing here is typed in by hand, so an example cannot disagree with the tool.
The cost base is well above the purchase price once buying, improving and selling costs are counted, and the gain is correspondingly smaller than the difference between the two prices. That gap is why records matter.
The losses come off before the discount, so each dollar of loss shelters a full dollar of gain rather than half of one. Applying them the other way round would waste half their value.
The whole gain is assessed, and the tax roughly doubles. Timing a sale across a twelve-month boundary is worth more than most of the optimisations people spend energy on.
The cost base is the purchase price plus acquisition costs, capital improvements and the costs of selling. Proceeds less that cost base is the gain, or a loss where it is negative.
Capital losses reduce the gain first. The discount is then applied to what remains, and the reduced amount is added to your other income for the year.
The order is not interchangeable. Applying the discount before losses would shelter the losses as well as the gain, which would understate the tax and overstate the losses you carry forward.
How every calculator on this site is built · Regulatory sources
An Australian resident individual
Companies get no discount, superannuation funds get a different one, and foreign residents are subject to rules of their own. None of those is modelled.
The asset is not your home
The main residence exemption can remove the gain entirely, and its partial forms — a home let for part of the ownership period, or one on a large parcel — are among the most intricate provisions in the system. None of that is modelled.
One CGT event in the year
A year with several disposals nets gains and losses across all of them before any discount. Running one disposal through here in isolation will not match that result.
The cost base is where the work is
What belongs in a cost base, and what has already been claimed as a deduction, is the part of a capital gains calculation that takes judgement. This calculator does the arithmetic on figures you have already decided.
Concessions and rollovers are excluded
The small business concessions, rollover relief, and pre-CGT assets can each remove or defer the tax entirely. None is modelled.
It is not a return
A capital gains schedule interacts with the rest of an assessment in ways one disposal cannot show. Use this to plan, and a tax agent to lodge.
Works out income tax and the Medicare levy on a resident individual’s taxable income, using the statutory rate scale for the income year you choose.
Works out what an investment property costs or returns each year: rent after vacancy, every holding cost, the loan, and the tax effect computed from the statutory scale.
Works out what is left after agent commission, marketing, legal fees and repaying the loan.
This calculator can be embedded on a business website, branded to match it, with a call to action that sends the enquiry to that business rather than collecting anything here.