You do not always need an accountant for capital gains tax, but for anything beyond a simple, well-documented sale, one usually saves you more than they cost. If you sold some shares and have clear records of what you paid and received, you can often report the gain yourself. Once property, a business, a large gain, an inheritance, or tax concessions are involved, capital gains tax gets complicated fast, and the mistakes are expensive. An accountant makes sure your cost base is right, applies every discount and exemption you are entitled to, and keeps you off the ATO’s radar. And because the fee is tax deductible, the real cost of getting it right is lower than it looks.
When you can handle CGT yourself
Some capital gains are simple enough to do on your own. If you sold shares or units through a broker, held them clearly for more or less than 12 months, and have records of the purchase and sale prices and costs, the calculation is fairly mechanical, and much of it may even be pre-filled or available from your broker’s tax report. For a single, clean sale with good records and a modest gain, doing it yourself through myTax is reasonable. The key is that you are genuinely confident about the cost base, the dates, and the 50% discount.
When you should use an accountant for CGT
CGT stops being simple as soon as any of these apply:
you sold a property, especially one that was rented out or used for business at some point
you sold a business or business assets, where small business concessions may apply
the gain is large, so the tax at stake is significant
you inherited the asset, or it came through a deceased estate
you sold cryptocurrency, particularly with many transactions
the asset is overseas, or you were a foreign resident for part of the ownership
you have capital losses from other years to bring in
In these cases the rules are detailed, the concessions are valuable, and an error can cost thousands. This is exactly where an accountant earns their fee.
How an accountant saves you money on CGT
The savings come from getting the details right, which is harder than it looks. An accountant makes sure your cost base includes everything it should, the purchase price plus buying and selling costs, stamp duty, and capital improvements, because a higher cost base means a lower gain. They apply the 50% discount correctly where you have held the asset for over 12 months. They claim the main residence exemption, in full or in part, on a property. For a business asset, they check whether the small business CGT concessions apply, which can reduce a gain to nothing. They bring in your capital losses from prior years, and they can advise on timing, such as delaying a sale into a lower-income year. Each of these can be worth far more than the fee.
Take a simple example. Someone sells an investment property with a $200,000 gain and, doing it themselves, forgets to include $30,000 of buying costs and improvements in the cost base and overlooks the 50% discount. They could overstate their taxable gain dramatically and pay many thousands more than they needed to. An accountant who gets the cost base and the discount right turns that around.
Accountant or financial adviser: which one?
It is worth being clear on the difference. An accountant handles the tax side of a capital gain: calculating it, applying concessions, and reporting it correctly. A financial adviser helps with the investment decision itself, whether to sell, what to do with the proceeds, and how it fits your broader plan. For the tax, you want an accountant, ideally a registered tax agent. For big decisions about your money, the two often work together. If your question is purely how this gain is taxed and how to pay the least tax legally, that is squarely an accountant’s job.
The mistakes people make doing CGT themselves
When people get CGT wrong on their own, it is usually one of a handful of errors: using the wrong cost base by leaving out purchase costs or improvements, missing the 50% discount, forgetting to apply capital losses, misjudging the main residence exemption on a property that was rented out, or simply not keeping the records needed to prove any of it. Some of these overstate the gain, so you overpay. Others understate it, which risks penalties when the ATO’s data matching catches the sale, and the ATO does track property and share sales closely. Either way, the cost of a mistake often dwarfs the cost of an accountant.
What an accountant needs from you for CGT
To handle a capital gain, your accountant needs the story of the asset from start to finish: what you paid for it and when, the costs of buying and selling, any money spent improving it, the sale price and date, and, for a property, records of any period it was rented out or used for a business. The better your records, the more accurately they can work out the gain and the more concessions they can safely claim. If your records are patchy, an accountant can often help reconstruct the cost base, but it is easier and cheaper if you kept the paperwork. Our tax planning checklist covers what to keep.
The cost against the saving
CGT is one area where the maths of using an accountant is usually clear. The tax at stake on a property or business sale is often tens of thousands of dollars, so even a small improvement in how the gain is calculated, or one concession correctly applied, can save many times the fee. The fee itself is tax deductible the following year, which lowers the real cost again. For a simple share sale the saving may not justify it, but for a significant or complex gain, an accountant almost always pays for themselves. If a sale is coming up, our business and tax advisers can look at it before you sell, which is when the planning options are still open.
