Selling an Investment Property? Here's How Much CGT You Could Legally Avoid — And the Window Most Austraians Miss

If you're selling an investment property in Australia, the most important financial decision you'll make isn't which agent you use or what price you accept. It's what you do — or don't do — in the months before settlement.

Capital gains tax is unavoidable on profitable property sales. But how much you pay is determined by timing, structure, and strategy. Most investors leave tens of thousands on the table simply because they don't know the rules — or leave it too late to use them.

Here's what you can legally do to reduce your CGT bill, and the specific window you have to act.

Capital gains tax is not a separate tax — it's added to your taxable income in the year you sell. At Australia's top marginal rate of 47%, a $300,000 capital gain could generate a $141,000 tax bill if you handle it the wrong way.

Handled correctly, that same gain could cost less than half that — or, in specific circumstances, nothing at all.

The ATO calculates your capital gain as: sale price minus your cost base (purchase price plus acquisition costs, capital improvements, and selling costs). The resulting gain is then discounted — if you've held the property for more than 12 months — before being added to your income.

After the 2026 federal budget, that discount has changed. The personal CGT discount on residential investment property has been reduced from 50% to 33% for high-income earners. That means the effective CGT rate for someone on the top marginal rate has jumped from 22.5% to approximately 30%.

This makes timing and structure more important than ever. See our full breakdown: legal CGT strategies for Australian property investors.

This is the single highest-value strategy available to most property investors — and it requires zero complex structures. It's simply about when in the financial year you settle.

Because CGT is added to your income in the year of settlement, selling in a year when your other income is lower can dramatically reduce the tax rate that applies to your gain.

Common scenarios where this applies:

• You're taking parental leave and will have significantly lower income next financial year
• You're retiring or reducing work hours and your income will drop substantially
• You have large deductible expenses in one year that will offset income
• Your partner is earning less in one year than the other

In practical terms: if you're planning to sell a property with a $400,000 gain, and you have a choice between settling in June versus July — one month's difference could mean settling in a lower-income year and saving $40,000–$80,000 in tax, depending on your marginal rate.

The window: Once you exchange contracts and settle, the CGT event is locked to that financial year. You cannot retroactively change it. The decision must be made before settlement — ideally before you even list the property.

If the property you're selling was ever your primary residence, the 6-year rule may significantly reduce — or eliminate — your CGT liability.

Under Section 118-145 of the Income Tax Assessment Act 1997, you can continue to treat a property as your main residence for up to six years after you move out, as long as you don't claim another property as your main residence during that time.

Here's how it works in practice: You buy a home in 2015, live in it until 2018, then rent it out. You sell in 2024 — six years after moving out. If you haven't claimed another main residence in that period, the entire gain from the period of rental may be CGT-exempt.

If you've lived there for part of the time and rented for part of the time, the exemption is apportioned. The calculation is based on the proportion of time the property was your main residence versus investment.

The catch: If you've claimed another property as your main residence in the same period, you cannot apply the 6-year rule. You must choose one property — and once you lodge, it's difficult to change. This is a decision worth modelling with a tax accountant before selling.

If the property is held jointly — 50/50, or in any other proportion — the capital gain is split accordingly between owners. Each owner pays tax on their share at their own marginal rate.

For a couple where one partner earns $180,000 and the other earns $55,000, a $300,000 gain split equally means:

• High earner pays 47% on $150,000 = ~$70,500
• Lower earner pays roughly 32.5% on $150,000 = ~$48,750
• Combined total = ~$119,250

The same property owned entirely by the high earner would cost ~$141,000. The income-splitting saves $21,750 on identical property performance.

If you're planning a future purchase with a partner, structuring it 50/50 from the outset preserves this option. Changing ownership structure after purchase triggers stamp duty and potentially CGT — so the time to plan is before you buy, not before you sell.

Any capital losses you've realised — from shares, other properties, or other CGT assets — can be used to offset the gain from your property sale. Losses must be applied before the 50% (or 33%) CGT discount is calculated.

If you're sitting on unrealised losses in a share portfolio, consider whether realising those losses before settlement makes sense. Timing the loss-realisation in the same financial year as your property gain directly reduces the taxable amount.

Example: $300,000 property gain, $80,000 in realised share losses = $220,000 net gain before discount. At the top marginal rate with the 33% discount, this saves approximately $24,000 in CGT compared to not realising the losses.

Carry-forward losses from previous years work the same way — the ATO tracks them automatically through your tax returns. If you've had losses in prior years that weren't fully used, they're available to absorb your property gain dollar-for-dollar.

If you're approaching retirement and your super balance is substantial, holding property inside an SMSF fundamentally changes the CGT equation.

In accumulation phase, an SMSF pays 10% effective CGT on properties held more than 12 months. In pension phase, it pays zero — on both capital gains and rental income.

After the 2026 budget, the gap between SMSF and personal CGT has widened considerably. High-income investors selling property personally now face an effective rate of approximately 30%. Inside a pension-phase SMSF, the rate is 0%. On a $400,000 gain, that's a $120,000 difference.

This isn't a strategy you can implement after deciding to sell — the property needs to be held inside the SMSF from the point of purchase. But if you're planning future property acquisitions and you're within 10–15 years of retirement, the SMSF structure deserves serious consideration. Read the full breakdown: Your SMSF pays 10% CGT. You pay 30%. Here's what smart investors are doing about it.

Your cost base isn't just the purchase price. These costs can all be included, reducing your taxable gain:

• Stamp duty on purchase
• Conveyancing and legal fees (purchase and sale)
• Building inspections and reports
• Capital improvements (renovations, additions — not maintenance)
• Agent commission on sale
• Marketing costs for the sale
• Costs of borrowing (loan establishment fees, mortgage insurance — but not ongoing interest if you've claimed it as a deduction)

Investors frequently understate their cost base because they don't keep records of smaller costs over many years. A thorough review of every expense since purchase — including any receipts for improvements — is worth doing before you sell. On a property held for 10+ years, the accumulated costs that belong in the cost base can be $30,000–$80,000, directly reducing your taxable gain dollar-for-dollar.

Important: Costs you've previously claimed as tax deductions (like repairs and maintenance) cannot also be included in the cost base. Capital improvements that were never deducted can be.

The window for most of these strategies closes at settlement. That means the time to act is before you engage an agent — not after you've accepted an offer.

Before listing, run through this checklist:

1. Check your settlement year. Is there a lower-income year coming? Can you time settlement to land in it?
2. Apply the 6-year rule test. Was this ever your primary residence? Have you maintained it as such for CGT purposes?
3. Review joint ownership structure. Are gains being split optimally between owners?
4. Identify capital losses. Do you have unrealised losses in other assets you could time to offset the gain?
5. Review your cost base. Have you captured every eligible cost since purchase?
6. Consider the impact on your super strategy. Does the after-tax outcome change how you're thinking about future property through an SMSF?

None of these strategies require aggressive tax planning. They're standard provisions within the Australian tax system — but they require planning. Investors who engage a specialist before listing consistently pay less CGT than those who ask about it after settlement.

If you want to see how property, tax strategy, and super work together in practice — including how one investor used these structures to grow $200,000 in 18 months — download the free $200K Property Case Study.

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Related reading: How to Avoid CGT on Investment Property: 7 Legal Strategies | Australia's CGT Discount Cut: What to Do Before 2027 | SMSF vs Personal: The CGT Gap After the 2026 Budget | Negative Gearing Australia: What's Actually Changing in 2027