Cost Base Explained: What You Can (And Can’t) Add To Reduce Capital Gains Tax

When you sell a property or asset in Australia, your Capital Gains Tax (CGT) liability is calculated based on the difference between what you paid and what you received. But what if you’ve spent money improving the asset or covering costs related to owning it? That’s where cost base adjustments and capital improvements come in. These adjustments can reduce your capital gain and, in turn, lower the tax you might owe.

In this article, we’ll break down what cost base adjustments and capital improvements are, how they affect your CGT, and what expenses you can include. We’ll walk you through examples and common scenarios to help you understand how these concepts work in real life.

What Is a Cost Base?

The cost base of an asset is essentially what it cost you to acquire, hold, and dispose of that asset. It’s used to calculate your capital gain or loss when the asset is sold. The higher your cost base, the lower your capital gain (and potentially your tax bill).

Elements of a Cost Base

According to the ATO, a cost base is made up of five elements:

1. Acquisition costs – What you paid to purchase the asset, including the purchase price and associated costs like stamp duty and legal fees.
2. Incidental costs – Costs incurred when acquiring or disposing of the asset, such as agent’s fees or advertising.
3. Ownership costs – Costs of owning the asset (e.g. interest, rates, and maintenance), provided the asset is not producing income.
4. Capital improvement costs – Costs spent on improving the asset, which we’ll explore in more detail shortly.
5. Title costs – Costs involved in preserving or defending your ownership of the asset.

What Are Cost Base Adjustments?

Cost base adjustments occur when you update or modify the components of your asset’s cost base over time. These adjustments usually happen when:

• You incur new costs that can be added to the cost base.
• You need to subtract amounts (e.g. capital works deductions already claimed).

When Do Cost Base Adjustments Apply?

Cost base adjustments are common in the following situations:

• Renovating a property.
• Subdividing land.
• Applying capital improvements that aren’t immediately deductible.
• Changing the use of a property (e.g. from main residence to rental).

Failing to adjust the cost base correctly can lead to paying more CGT than necessary.

Capital Improvements Explained

A capital improvement is work done on an asset that increases its value or extends its life. This differs from general maintenance or repairs, which are usually tax-deductible if the asset is income-producing.

Examples of Capital Improvements

• Building an extension or granny flat
• Installing a new kitchen or bathroom
• Constructing a garage or shed
• Upgrading wiring or plumbing systems

These improvements can be added to your cost base, provided they haven’t already been claimed as a tax deduction.

The Interaction Between Capital Improvements and CGT

When it comes to CGT, capital improvements increase your cost base. This reduces the capital gain when you eventually sell the asset.

For example:

• You bought a house for $600,000.
• You spent $80,000 on a major renovation.
• You sold the house for $850,000.

Without the improvement, your gain would be $250,000. With the capital improvement added to the cost base, your gain reduces to $170,000.

Important Note on Depreciation and Capital Works

If you’ve claimed depreciation or capital works deductions on the improvement (for a rental property, for instance), those amounts must be excluded from the cost base to avoid double-dipping.

Special Considerations

Main Residence Exemption

If the property is your main residence throughout the ownership period, CGT might not apply at all. But if the property was rented out for a period, you’ll need to calculate a partial exemption, factoring in capital improvements made while it was rented.

Subdivided Land or Partial Sales

If you subdivide land and sell a portion, you need to apportion the original cost base and include any improvements related specifically to that portion.

Inherited Properties

The cost base of inherited property is generally the market value at the date of death (if the asset was acquired before 20 September 1985). Any capital improvements made after this date may be added to the cost base.

Keeping Records: A Must for Cost Base Adjustments

To claim cost base adjustments or capital improvements, you must have proper records. These include:

• Invoices and receipts
• Bank statements
• Contracts
• Council approvals (for renovations)

Without this documentation, the ATO may disallow the adjustment.

Final Thoughts: Get the Full Benefit of Your Investment

Understanding cost base adjustments and capital improvements can make a substantial difference to your CGT outcome. Many Australians miss out on valuable deductions simply because they don’t keep records or misunderstand what counts.

If you’re unsure about your situation, consider speaking with a tax agent or accountant who specialises in CGT. A little advice can go a long way when you’re dealing with capital gains.

By ensuring you properly adjust your cost base and include capital improvements, you can reduce the taxable portion of your gain and keep more of your hard-earned profit. That’s a win every Australian property investor or asset holder can appreciate.