For Australian investors, capital gains tax shares refers to tax on profits when shares are sold for more than their cost. The gain is added to assessable income and taxed at the investor’s marginal rate. Assets held for at least 12 months may qualify for a 50% discount, while capital losses can offset capital gains.
Capital gains tax is the tax you pay on profits from selling investments like ASX shares and exchange-traded funds (ETFs). Unlike dividends, which are taxed as income when you receive them, CGT only applies when you actually sell an asset for more than you paid for it. Understanding how CGT works—and more importantly, how to manage it—can mean the difference between building genuine wealth and watching it slip away to the tax office.
This explainer will walk you through everything you need to know about capital gains tax as an ASX investor, from the fundamentals through to advanced strategies that can help you keep more of your profits.
What Is Capital Gains Tax?
Capital gains tax is a tax on the profit you make when you sell an asset for more than you paid for it. The Australian Taxation Office (ATO) applies CGT to most investments, including shares, ETFs, managed funds, and investment properties.
When you buy 1,000 shares in a blue-chip ASX company at $10 per share for $10,000, and later sell them at $15 per share for $15,000, you’ve made a capital gain of $5,000. That $5,000 profit is subject to capital gains tax.
It’s crucial to understand that capital gains tax only applies when you dispose of (sell) an asset. Simply holding shares that increase in value doesn’t trigger a tax obligation. You could own a share worth $50,000 more than you paid for it, and as long as you don’t sell, you won’t owe CGT. This timing aspect is why many sophisticated investors use CGT planning as part of their overall investment strategy.
Capital gains are added to your assessable income and taxed at your marginal tax rate. For Australian residents, this means your CGT is taxed according to your income tax bracket, which for 2026–27 runs from nil below the $18,200 tax-free threshold up to 45% plus the 2% Medicare levy for high-income earners.
How does capital gains tax work on shares in Australia?
One of the most valuable features of the Australian tax system for long-term investors is the capital gains tax discount. If you’ve held an asset for at least 12 months before selling it, you’re eligible for a 50% discount on the capital gain.
Here’s how it works in practice. Let’s say you bought shares for $10,000 and sold them for $15,000 after holding them for 13 months. Your capital gain is $5,000. With the 50% CGT discount, only $2,500 of that gain is added to your assessable income. If you’re in the 37% tax bracket (plus the 2% Medicare levy), you’d pay tax on $2,500 at 39%, which equals $975 in tax. Without the discount, you’d pay 39% on the full $5,000 gain, which would be $1,950.
The 50% discount effectively halves your tax bill on long-term capital gains, making it a powerful incentive to hold investments for the required 12 months. This is why the holding period is so critical in CGT planning.
It’s important to note that the 12-month holding period is measured from the day after you acquire the asset to the day you dispose of it. If you buy shares on June 1 and sell them on June 2 the following year, you’ve held them for more than 12 months and qualify for the discount. However, if you sell on May 31, you haven’t yet reached the 12-month mark and won’t qualify.
How CGT Calculations Work: Step by Step
Calculating your capital gains tax liability involves several steps, and understanding each one is essential for effective tax planning.
Step 1: Determine Your Cost Base
Your cost base is the starting point for any CGT calculation. It includes not just the purchase price of the shares, but also any incidental costs of acquiring them. These might include brokerage fees, advisor fees, or the cost of obtaining investment advice specifically related to acquiring that asset.
For example, if you buy $10,000 worth of ASX shares and pay $50 in brokerage, your cost base is $10,050, not $10,000. This is an often-overlooked detail that can help reduce your capital gain.
Step 2: Calculate the Capital Gain or Loss
Your capital proceeds are what you receive on the sale. Brokerage paid to sell is added to your cost base as an incidental cost, rather than deducted from your proceeds — the gain comes out the same, but only the cost base treatment is right.
If you sell those same shares for $15,000 and pay $50 in brokerage, your proceeds are $15,000 and your cost base becomes $10,100. Your capital gain is $15,000 minus $10,100 = $4,900.
Step 3: Apply the 12-Month Holding Period Test
If you’ve held the asset for 12 months or more, you can apply the 50% discount. In our example, if you held the shares for 13 months, your discounted capital gain is $4,900 × 50% = $2,450.
Step 4: Add to Your Assessable Income
Your capital gain (or discounted capital gain) is added to your other income for the financial year. This might include salary, rental income, dividends, and interest.
Step 5: Calculate Tax at Your Marginal Rate
The tax on your capital gain is calculated at your marginal tax rate. If you’re in the 37% tax bracket (plus 2% Medicare levy = 39%), you’d pay 39% on your discounted capital gain of $2,450, which equals $955.50. You can run your own figures through our free CGT calculator.
How do you calculate capital gains tax on shares in Australia?
Not every investment is a winner. When you sell an asset for less than you paid for it, you’ve made a capital loss. While losses aren’t pleasant, they can be valuable for tax purposes.
Capital losses can be used to offset capital gains. If you made $5,000 in capital gains from one share sale and $2,000 in capital losses from another, you can net these together to get a net capital gain of $3,000. This is where tax-loss harvesting comes in.
Tax-loss harvesting is the strategy of deliberately selling investments at a loss to offset capital gains elsewhere in your portfolio. The goal is to reduce your overall tax liability while maintaining your desired portfolio allocation.
Here’s a practical example. Suppose you have an ASX technology ETF that’s down 15% from your purchase price. At the same time, you’ve made significant gains in your bank shares. You could sell the technology ETF at a loss to harvest that loss, then immediately buy a similar (but not identical) technology ETF to maintain your portfolio exposure to the tech sector. The loss from the first ETF offsets your gains from the bank shares, reducing your overall CGT liability.
There’s an important caveat here: the ATO has rules against “wash sales,” though they use different terminology. Australia has no codified wash-sale rule and no day count at all: no number of days makes a repurchase safe, and none makes it unsafe. What applies instead is Part IVA of the Income Tax Assessment Act 1936, and the Commissioner’s view is set out in TR 2008/1, which says the term wash sale “does not have any precise meaning”. This is designed to prevent investors from claiming losses while maintaining the same investment.
The key is to ensure the replacement asset is genuinely different from the one you sold. If you sell an ASX bank ETF at a loss and buy one with a genuinely different mandate, your economic exposure has actually changed. Buying back something that leaves your position effectively the same is the pattern Part IVA is aimed at, and no waiting period cures it.
Do you pay capital gains tax on shares in Australia?
The 12-month holding period is one of the most important factors in CGT planning. Let’s look at how dramatically it can affect your tax outcome.
Consider an investor who buys $50,000 worth of ASX shares and sells them for $60,000, making a $10,000 capital gain. They’re in the 37% tax bracket (39% including Medicare levy).
If they sell after 11 months (no discount):
- Capital gain: $10,000
- Tax at 39%: $3,900
- After-tax profit: $6,100
If they sell after 13 months (with 50% discount):
- Capital gain: $10,000
- Discounted gain: $5,000
- Tax at 39%: $1,950
- After-tax profit: $8,050
The difference is $1,950. By simply waiting two extra months, this investor keeps an additional $1,950 of their profit. Over a lifetime of investing, these decisions compound significantly.
This is why understanding how the 50% CGT discount works in Australia and planning around the 12-month holding period is so critical. Many ASX investors make rebalancing decisions without considering the tax implications, costing themselves thousands in unnecessary taxes.
Parcel-Level Lot Selection and Cost Base Methods
When you own multiple parcels of the same share or ETF—perhaps because you’ve bought at different times or prices—you have choices about which parcel to sell. This is where parcel-level lot selection becomes strategically important.
FIFO, LIFO, specific identification and highest-cost-first are not four elections you register with the ATO. They are shorthand for which parcel you nominate. Taxation Determination TD 33 puts the choice on you: the Commissioner accepts first-in-first-out as a reasonable basis, and equally accepts your own selection, provided your records support it. What you cannot do is average the cost base across parcels bought on different days.
Which parcel you nominate changes the tax, and not always in the direction you expect, because the 12-month discount can matter more than the size of the gain. We work through the mechanics, with worked examples, in how tax lot tracking works in Australia, and compare the methods side by side in FIFO vs specific identification for ASX share parcels.
The choice of parcel can change your tax bill substantially, which is why it is worth deciding before you place the sell order rather than after it.
This is where tools that provide parcel-level visibility become invaluable. Rather than guessing which shares you’re selling, you can see exactly how each parcel selection affects your tax outcome before you make the trade. Crowdfolio’s portfolio tracker provides this parcel-level forecasting, comparing minimise-tax, FIFO, LIFO and highest-cost-first outcomes upfront so you can make tax-aware trading decisions.
Part IVA and Wash Sale Considerations
While tax-loss harvesting is a legitimate strategy, the ATO has rules to prevent aggressive tax planning that lacks genuine commercial substance. One of the most important is Part IVA of the Income Tax Assessment Act.
Part IVA is an anti-avoidance rule that allows the ATO to disallow tax benefits (including capital losses) if they were the main purpose of a scheme. The rule is broad and somewhat subjective, which is why it’s important to understand the principles.
For example, if you repeatedly sell shares at a loss and immediately rebuy them at a slightly higher price, purely to generate losses for tax purposes without any genuine investment reason, the ATO might view this as a Part IVA scheme and disallow the losses.
The key to staying on the right side of Part IVA is ensuring your investment decisions have a genuine commercial purpose beyond just generating tax losses. If you’re rebalancing your portfolio because your allocation has drifted away from your target (which is a legitimate investment reason), harvesting losses in that process is fine. If you’re selling and rebuying the identical asset purely for the tax loss, you’re in riskier territory however long you wait: the ATO’s own worked example in TA 2008/7 concerns a repurchase made 24 hours later.
As noted earlier, there is no wash-sale statute here and no waiting period to satisfy. The question Part IVA asks is whether your economic exposure genuinely changed, which means buying something materially different rather than counting days.
Dividend Reinvestment Plans and CGT
Many ASX investors use dividend reinvestment plans (DRPs) to automatically reinvest dividends back into shares. While this is a great strategy for compounding returns, it has CGT implications.
When dividends are reinvested through a DRP, you’re acquiring new shares at the current market price. Each DRP purchase creates a new parcel with a new cost base and acquisition date. Over time, you can accumulate many different parcels with different cost bases and holding periods.
Each reinvestment is a separate CGT asset with its own cost base and acquisition date, so your records need to capture every DRP allocation. It also leaves you more parcels to choose between when you eventually sell. ETF and managed fund distributions add a further step, because the annual tax statement carries cost base adjustments you have to apply: see how ETF distributions and capital gains are taxed in Australia.
Timing Strategies and Financial Year Planning
Because CGT is assessed on a financial year basis (July 1 to June 30 in Australia), there’s strategic value in timing your trades around the financial year.
If you’re in a year where you’ve already realized significant capital gains, you might defer selling other profitable positions until the next financial year to spread your tax liability. Conversely, if you’re in a year with low income or significant losses, it might be advantageous to realize some gains to use up your lower tax bracket.
You can also use tax-loss harvesting strategically near the end of the financial year. If you’ve realized large gains in June and want to offset them, you can harvest losses on underperforming positions before June 30 to reduce your overall CGT liability for that year.
This kind of planning requires visibility into your portfolio’s tax position throughout the year, not just at tax time. Many ASX investors only think about CGT when they’re preparing their tax return in July, but by then it’s too late to implement most strategies. If rebalancing is what triggers your sales, our guide to rebalancing your portfolio with CGT in mind works through the trade-offs. Crowdfolio’s CGT forecasting lets you see your tax position in real-time, so you can make informed trading decisions throughout the year.
How much is capital gains tax on shares in Australia?
Australian tax policy around capital gains tax has evolved over time, and it’s important to stay informed about changes that might affect your planning.
The capital gains tax regime is changing, and the change is law rather than a proposal. What the capital gains tax and negative gearing changes mean for investors sets out what changed and when it applies.
Currently, the 50% CGT discount applies to assets held for 12 months or more. From 1 July 2027 the 50% discount is replaced, for individuals and trusts, by cost base indexation, together with a 30% minimum tax rate on net capital gains and a deemed disposal and reacquisition on 1 July 2027. Royal assent was given on 26 June 2026. Everything described above remains the law for CGT events up to and including 30 June 2027.
It’s important to stay informed about potential changes and to review your tax strategy periodically. What’s optimal today might change if the tax rules change. Working with a tax professional and using tools that help you forecast tax outcomes can help you adapt to changes as they occur.
Understanding Your Marginal Tax Rate
Your capital gains tax bill depends significantly on your marginal tax rate—the tax rate you pay on your last dollar of income. This is why understanding your tax bracket is so important for CGT planning.
For the 2026–27 financial year, Australian resident tax brackets are:
- $0–$18,200: No tax
- $18,201–$45,000: 15%
- $45,001–$135,000: 30%
- $135,001–$190,000: 37%
- $190,001 and above: 45%
Plus the Medicare levy of 2% (or higher for high-income earners without private health insurance).
If you’re in the $190,001+ bracket, your marginal rate is 47%, meaning every dollar of capital gain adds 47 cents to your tax bill. For someone in the $18,201–$45,000 bracket, the marginal rate is 15%, or 17% with the Medicare levy, making the tax impact significantly lower.
This is why some high-income earners deliberately time capital gains realization to spread them across multiple financial years, potentially moving themselves into lower tax brackets in some years.
The Importance of Record-Keeping
Effective CGT management depends on meticulous record-keeping. You need to maintain records of:
- Purchase details: Date, quantity, price, and brokerage for each share or ETF purchase
- Sale details: Date, quantity, price, and brokerage for each sale
- Dividend reinvestments: Date, quantity, and price for each DRP transaction
- Corporate actions: Stock splits, mergers, or other corporate events that affect your holdings
- Cost base adjustments: AMIT cost base adjustments from your ETF or managed fund annual tax statement, which arrive every year and are not optional
The ATO requires you to keep records for five years after the transaction, but keeping them longer is prudent. Without accurate records, you can’t:
- Prove your cost base to the ATO if questioned
- Determine your holding period for the 12-month discount
- Use specific identification or other lot selection methods
- Prepare accurate tax returns
Many ASX investors rely on their broker’s statements, but brokers don’t always provide all the information you need (like brokerage costs included in your cost base). This is why maintaining your own records, or using a portfolio tracking tool, is important.
Tools like Crowdfolio’s portfolio tracker can help by importing your transaction data from CSV exports, with templates for SelfWealth, Stake and CMC Markets plus a generic template for other brokers. This creates an auditable record of your holdings and transactions, making it easier to calculate your CGT liability accurately.
Practical Steps to Optimize Your CGT Position
Now that you understand how CGT works, here are practical steps you can take to optimize your tax position:
1. Plan Around the 12-Month Holding Period
If you’re considering selling a profitable position, check how long you’ve held it. If you’re close to the 12-month mark, waiting a few weeks or months to qualify for the 50% discount could significantly reduce your tax bill.
2. Harvest Losses Strategically
Identify underperforming positions in your portfolio. If you’re considering selling them anyway, do so before the financial year ends to harvest the loss and offset other gains. If you want to keep exposure to that sector, buy something materially different rather than relying on a waiting period: Australia has no wash-sale clock to run down.
3. Use Parcel-Level Selection
When selling shares or ETFs, decide which parcel you are disposing of rather than letting FIFO happen by default. Specifically identify which parcel you’re selling to optimize your tax outcome. If you have parcels with different cost bases and holding periods, you have flexibility to choose the most tax-efficient outcome.
4. Monitor Portfolio Drift
As your investments grow at different rates, your portfolio allocation drifts from your target. Rebalancing is a legitimate investment reason to trade, and you can harvest losses in the process. This combines good portfolio management with tax efficiency.
5. Keep Meticulous Records
Maintain detailed records of all transactions, including dates, quantities, prices, and brokerage. This is essential for accurate CGT calculations and for defending your position if the ATO questions your returns.
6. Plan Across Multiple Years
If you have large capital gains, consider spreading the realization across multiple financial years to manage your tax bracket and overall tax liability.
7. Use the Right Tools
Leverage technology to make CGT planning easier. A portfolio tracker that provides upfront CGT forecasting, parcel-level visibility, and accountant-ready reports can transform CGT management from a compliance chore into a strategic advantage.
Conclusion
Capital gains tax is a complex but manageable aspect of investing in ASX shares and ETFs. By understanding how CGT works—from basic calculations through to advanced strategies like tax-loss harvesting and parcel-level lot selection—you can make more informed trading decisions and keep more of your investment profits.
The key is to think about tax before you trade, not after. By considering the CGT implications of your trading decisions upfront, you can align your investment strategy with your tax situation. The 12-month holding period, the 50% discount, loss harvesting opportunities, and parcel-level lot selection all provide levers you can use to optimize your outcomes.
Remember that Australian capital gains tax rules are detailed and can be complex, especially when dealing with multiple parcels, different holding periods, and wash sale considerations. While this explainer provides a comprehensive overview, consulting with a qualified tax professional is recommended for personalized advice.
By combining a solid understanding of how CGT works with the right tools and professional guidance, you can build a tax-efficient investment portfolio that maximizes your long-term wealth creation.