What is a Capital Gains Tax Calculator?

A capital gains tax calculator estimates the tax you’ll pay when you sell an asset — an investment property, shares, ETFs, or cryptocurrency — for more than it cost you. In Australia, CGT isn’t a separate tax with its own rate: your net capital gain is added to your taxable income for the year and taxed at your marginal income tax rate. That’s why two people selling the same property for the same profit can pay very different amounts of CGT.

This calculator builds your complete cost base (purchase price plus buying costs, selling costs, and capital improvements), applies prior-year capital losses, applies the 50% CGT discount for assets held over 12 months, and then calculates the actual extra tax by comparing your tax bill with and without the gain — the same way the ATO does it.

How is Capital Gains Tax Calculated in Australia?

The calculation has four stages: work out the cost base, subtract it from your sale proceeds to get the gross gain, apply losses and the discount to get the taxable gain, then calculate the tax on your income with the gain stacked on top.

Example: You bought an investment property for $550,000 with $25,000 of purchase costs, spent $30,000 on a renovation, and sold it for $780,000 with $18,000 of selling costs after owning it 6 years. Cost base = $623,000, gross gain = $157,000, taxable gain after the 50% discount = $78,500. On a $95,000 salary, that gain pushes you into higher brackets and the CGT comes to roughly $27,000 — leaving you about $130,000 of after-tax profit.

How to Use This CGT Calculator

Select the asset type and whether you held it for more than 12 months. Enter the purchase price, sale price, and your purchase costs, selling costs, and capital improvements — these all reduce your gain, so don’t skip them. Add any carried-forward capital losses from previous years. Finally, enter your taxable income excluding the gain — this determines which tax brackets the gain falls into. Hit Calculate to see your CGT, after-tax profit, effective tax rate on the gain, and the full step-by-step breakdown.

What Your Results Mean

The headline figure is the extra tax the gain adds to your return — what you’ll actually owe the ATO. The gross gain is your raw profit before any concessions. The taxable gain is what’s added to your income after losses and the 50% discount. Net profit after tax is what you genuinely keep, and the effective tax rate on the gain shows the real percentage of your profit going to tax — usually far less than your marginal rate thanks to the discount.

Is This Calculator Accurate?

The calculator uses the exact 2025–26 resident tax brackets plus the 2% Medicare levy and stacks the gain on your income precisely as the ATO does. What it can’t capture: depreciation you’ve claimed (which reduces your cost base on property), partial main residence exemptions, the 6-year absence rule, foreign resident rules (no discount), and entity differences — companies get no discount and SMSFs get 33.3% instead of 50%. For straightforward individual sales it’s a close estimate; for anything with a depreciation schedule or residence history, see an accountant.

How to Choose Your Inputs

Purchase costs: Include stamp duty, conveyancing, building and pest inspections, and buyer’s agent fees — these are commonly forgotten and directly reduce your gain. Capital improvements: Renovations, extensions, a new kitchen — but not repairs or maintenance you’ve already claimed as deductions on a rental. Selling costs: Agent commission (typically 1.5–2.5%), marketing, and conveyancing. Capital losses: Losses from shares or crypto sold in previous years carry forward indefinitely and offset this gain before the discount — apply them here for an accurate result.

Suitable for Women

Yes — CGT rules apply identically to everyone, but there’s a planning point worth knowing for couples: jointly owned assets split the gain 50/50, so each partner pays tax at their own marginal rate. If one partner has taken time out of the workforce and has a lower income, their half of the gain is taxed in lower brackets — sometimes saving thousands compared with the asset being held solely by the higher earner. Ownership structure matters most when decided at purchase, not at sale.

Suitable for Men

Yes — the same rates and discount apply. One timing strategy relevant to higher earners: because the gain is taxed in the year the contract is signed, deferring a sale from June into July pushes the tax bill a full financial year later, and selling in a year when your income is lower (career break, retirement, sabbatical) means the gain stacks onto lower brackets. A $100,000 taxable gain costs roughly $47,000 on a $200,000 income but closer to $32,000 on a $60,000 income.

Can I Use This for Crypto and Shares?

Yes — the CGT rules for cryptocurrency and shares are the same as for property: cost base, gross gain, losses, 50% discount over 12 months, taxed at marginal rates. For crypto, every disposal is a CGT event — including swapping one coin for another, not just cashing out to dollars. For shares, your cost base includes brokerage on both the buy and the sell. Select “Shares” or “Cryptocurrency” in the asset type dropdown and enter your figures the same way; the maths is identical.

Common Mistakes to Avoid

• Forgetting purchase costs in the cost base. Stamp duty alone can be $20,000–$40,000 — leaving it out massively overstates your taxable gain.
• Selling just before the 12-month mark. The 50% discount needs ownership of more than 12 months, measured contract date to contract date.
• Counting repairs as capital improvements. Repairs claimed as rental deductions can’t also be added to the cost base — that’s double dipping and the ATO data-matches it.
• Ignoring depreciation claw-back on property. Capital works deductions you’ve claimed reduce your cost base, increasing the gain — a frequent and expensive surprise.
• Forgetting crypto-to-crypto swaps are taxable. Trading ETH for SOL is a disposal of ETH at market value, even though no dollars touched your bank account.

Limitations of This Calculator

This calculator handles the standard individual CGT calculation. It does not model the main residence exemption or partial exemptions (where a property was your home for part of the ownership period), the 6-year absence rule, depreciation adjustments, the foreign resident CGT regime, small business CGT concessions, or the different discounts for SMSFs (33.3%) and companies (nil). It also applies the gain in a single year — large gains genuinely do push income into the top brackets, which is correct, but staged disposals across financial years can sometimes reduce total tax. For official guidance, see the ATO’s capital gains tax pages.

Frequently Asked Questions