How to Calculate Capital Gains Tax (CGT) in Australia: Examples, Rules and Tips

Selling an investment property, shares or another asset for more than you paid can leave you with a capital gain. In Australia, that gain may increase the amount of income tax you need to pay. Understanding how to calculate Capital Gains Tax (CGT) before selling an asset can help you estimate the tax impact and keep the right records.

The calculation is not always as simple as subtracting the purchase price from the selling price. Eligible purchase and sale expenses, capital improvements, capital losses, ownership periods and available exemptions can all affect the result.

If you are unsure how an asset sale could affect your taxable income, speaking with a tax accountant in Perth can help you understand the relevant CGT rules, review eligible expenses and identify any exemptions that may apply to your circumstances.

This guide explains how to calculate CGT in Australia, with a worked investment property example and practical points to consider before lodging your tax return.

What Is Capital Gains Tax in Australia?

Capital Gains Tax is the tax treatment that applies when you make a capital gain from disposing of an asset. Despite its name, CGT is not a separate tax. A net capital gain is generally included in your assessable income and taxed at your applicable income tax rate.

CGT can apply to assets such as:

Investment properties and vacant land

Shares and managed fund investments

Cryptocurrency, where the transaction is a CGT event

Other eligible investment assets

Your main residence may qualify for a full or partial exemption, depending on your circumstances.

The Australian Taxation Office (ATO) provides detailed guidance on how capital gains tax works.

How to Calculate Capital Gains Tax in Australia

To calculate a capital gain, you generally subtract the asset's cost base from the capital proceeds received when you dispose of it.

Basic calculation:

Capital gain = Capital proceeds − Cost base

However, the final amount included in your tax return may be lower after applying eligible capital losses, the CGT discount or other relevant rules.

A practical calculation involves these steps.

Step 1: Work Out Your Capital Proceeds

Capital proceeds usually include the money you receive from selling an asset. Depending on the transaction, they can also include the market value of property or other benefits received.

For example, if you sell an investment property for $750,000, your starting capital proceeds would generally be $750,000, subject to any applicable adjustments.

The contract date is generally important when determining the CGT event for a property sale. The relevant event usually occurs when you enter into the sale contract, rather than on the settlement date.

Step 2: Calculate the Cost Base

The cost base is the amount used to work out your capital gain. It can include more than the original purchase price.

Depending on the circumstances, eligible expenses may include:

The purchase price of the asset

Stamp duty and eligible conveyancing or legal costs associated with the purchase

Certain costs directly related to buying or selling the asset

Eligible capital expenditure, such as structural improvements

Certain ownership costs where the relevant rules allow them

Not every expense can be included. For example, expenses already claimed as a tax deduction generally cannot also be included in the cost base to the extent the tax rules prevent double counting. Some capital works deductions may also require an adjustment.

Keeping purchase contracts, settlement statements, invoices and improvement records can make this calculation much more reliable.

Accurate financial records are particularly important when calculating a capital gain. Professional accounting services in Perth can help you organise purchase documents, eligible improvement expenses and sale records so that the relevant figures are easier to review when preparing your tax return.

Step 3: Subtract the Cost Base from the Capital Proceeds

Once you have identified the relevant proceeds and cost base, subtract one from the other.

If the result is positive, you generally have a capital gain. If the calculation produces a loss, you may have a capital loss, subject to the applicable CGT rules.

A capital loss is not automatically a deduction against your salary or ordinary business income. It is generally used to offset capital gains.

Step 4: Apply Capital Losses and Any Eligible CGT Discount

If you have eligible capital losses from the current year or unapplied net capital losses from earlier years, these generally need to be applied before calculating the CGT discount.

Individuals and trusts may generally qualify for a 50% CGT discount on eligible assets held for at least 12 months, subject to the relevant conditions. Companies generally cannot claim this discount.

The holding period, type of asset, ownership structure and acquisition date can affect which calculation method is available.

Step 5: Include the Net Capital Gain in Your Tax Return

After working through the applicable rules, you calculate your net capital gain for the income year. This amount is generally included in your assessable income.

The amount of additional tax payable depends on your overall taxable income, applicable tax rates and other relevant circumstances. Therefore, a capital gain of $20,000 does not automatically mean you owe $20,000 in tax, nor does a 50% CGT discount mean your tax bill is reduced by 50%.

CGT Calculation Example: Selling an Investment Property

Consider an individual who sells an investment property in Australia. The following figures are illustrative and assume the expenses qualify for inclusion in the cost base.

In this example, the individual's net capital gain would be $110,000, assuming the individual qualifies for the 50% discount and no other adjustments apply.

The $110,000 is generally included in the individual's assessable income. It is not the final CGT bill. The additional tax depends on the person's total taxable income and circumstances.

Actual property calculations may differ where the main residence exemption, capital works deductions, private use, ownership changes or other adjustments apply.

If you are selling a rental property, the calculation may need to account for capital improvements, selling expenses and capital works deductions claimed in previous years. Getting advice on capital gains tax in Perth through a qualified tax professional can help you understand which adjustments may apply before you finalise your tax return.

You can explore Palladium Financial Group's tax accountant services to learn more about relevant tax support.

How Does the 50% CGT Discount Work?

The CGT discount can reduce an eligible capital gain, but it is not available for every asset or taxpayer.

For individuals and trusts, the general requirements include holding the asset for at least 12 months and satisfying the other relevant conditions. Companies generally do not receive the 50% discount.

For example, if an eligible individual has a $40,000 capital gain and no capital losses, the gain may be reduced to $20,000 under the discount method.

The calculation changes if capital losses are available. Those losses are generally applied before the discount.

For assets acquired before 21 September 1999, special transitional rules may allow a choice between the discount and indexation methods, depending on the circumstances. Some assets and transactions also have special rules.

It is worth checking the applicable method rather than assuming that the 50% discount will always produce the best result.

What Happens If You Make a Capital Loss?

A capital loss occurs when the relevant proceeds are less than the asset's reduced cost base. The reduced cost base is similar to the cost base but has different rules for certain elements.

Capital losses can generally be used to reduce capital gains in the same income year. Unused net capital losses can generally be carried forward to offset eligible capital gains in later income years.

However, capital losses cannot generally be deducted from wages, salary or ordinary business income.

If you sell several investments during the same financial year, calculating each gain and loss separately can help you determine the correct net capital gain.

Does CGT Apply When You Sell Your Home?

A property used as your main residence may qualify for a full or partial main residence exemption. Whether you qualify depends on factors such as how the property was used, the period you lived there, whether it earned rental income and whether another property was treated as your main residence.

If you rented out your home, used part of it to produce income or moved out and rented it to tenants, the exemption may be limited.

Foreign residency, changes in use and other special circumstances can also affect eligibility. Do not assume that every property you have lived in is automatically exempt from CGT.

Common CGT Calculation Mistakes to Avoid

A few errors can make a noticeable difference to your calculation.

Leaving out eligible expenses: Missing purchase costs, selling expenses or qualifying capital improvements can result in an incorrect cost base.

Including expenses twice: An expense already claimed as a deduction may not be eligible to be included again in the cost base.

Ignoring capital losses: Current-year and carried-forward capital losses can affect your net capital gain.

Assuming the discount always applies: The 12-month holding requirement and other eligibility rules need to be checked.

Using the wrong sale date: For property, the CGT event generally occurs when the sale contract is entered into, not when settlement takes place.

Overlooking the main residence rules: A property that has been rented out or used for business may require a more detailed calculation.

Treating the capital gain as the tax payable: The net capital gain generally forms part of assessable income; the resulting tax depends on the taxpayer's overall circumstances.

When preparing your annual return, make sure your capital gains and losses are reported correctly and that supporting records are available. Professional tax return services in Perth may help you review the relevant information and report your net capital gain in line with applicable tax requirements.

When Should You Speak to a Tax Accountant?

Professional advice may be useful if you are selling an investment property, have several capital gains and losses, have owned an asset for different periods, or are unsure whether an exemption or discount applies.

The calculation can become more complicated when a property has been rented out, capital works deductions have been claimed, ownership has changed, or the asset is held through a trust or company.

A tax professional can help you review the relevant documents, understand the applicable CGT rules and identify issues that may affect your tax return.

Palladium Financial Group provides tax and accounting support for individuals and businesses in Perth. If you need assistance understanding the tax implications of an asset sale, explore our tax accounting services in Perth or visit Palladium Financial Group to learn more about our services.

Frequently Asked Questions

How do I calculate CGT in Australia?

Start with the capital proceeds and subtract the applicable cost base to determine the capital gain. Then consider capital losses, any eligible CGT discount, exemptions and other relevant adjustments to calculate the net capital gain.

Is CGT calculated on the full selling price?

No. The calculation generally considers the capital proceeds less the relevant cost base. Eligible expenses and other adjustments can affect the amount of the gain.

Do I pay 50% tax on my capital gain?

No. The 50% CGT discount is a reduction that eligible taxpayers may apply to certain capital gains. The resulting net capital