Capital Gains Tax on Australian Investment Property: The 50% Discount Trap
Australian CGT on property looks simple — sell after 12 months and get 50% off. But cost base mistakes, timing traps, and interaction with negative gearing catch investors. 2026 guide.
Part 5 of the Property Investment Gotchas 101 series.
Capital Gains Tax (CGT) is the tax you pay on the profit when you sell an investment property in Australia. The gain is the sale price minus your cost base (what you paid plus certain costs). Hold for more than 12 months and you get a 50% discount — only half the gain gets added to your taxable income. Source: ATO — Property and capital gains tax.
The Basics
Quick example:
| Item | Amount |
|---|---|
| Sale price | $800,000 |
| Less: Cost base | -$620,000 |
| Capital gain | $180,000 |
| 50% CGT discount (held > 12 months) | -$90,000 |
| Taxable capital gain | $90,000 |
That $90,000 gets lumped on top of your other income for the year. If you’re already on $90,000 salary, your total jumps to $180,000 — pushing a chunk of the gain into the 37% bracket (and close to 45% territory).
Key Takeaway
The 50% discount trap: people assume they’ll pay half their normal tax rate on the gain. Nah. The discounted amount gets stacked ON TOP of everything else, which can push you into a higher bracket. The actual tax hit is often bigger than expected.
What Goes in Your Cost Base (And What Doesn’t)
Your cost base matters because every dollar in it means a dollar less in taxable gain.
Counts:
- Purchase price
- Stamp duty you paid at purchase
- Legal and conveyancing fees (buying and selling)
- Agent fees at sale
- Building and pest inspections
- Capital improvements (reno, extension, new fixtures)
- Borrowing costs you haven’t already claimed as deductions
Doesn’t count:
- Costs you’ve already claimed as tax deductions (repairs, maintenance)
- Depreciation claimed on plant and equipment — that gets added back
- Insurance, rates, and management fees already deducted year-by-year
The trap: Renos and improvements boost your cost base, but only if they’re capital work. Repainting a wall the same colour is a repair (deductible annually). Gutting the kitchen is an improvement (goes into cost base). The difference matters: repairs cut your annual tax but don’t help CGT; improvements don’t help annual tax but DO shrink your CGT bill.
The Depreciation Clawback
If you’ve been running negative gearing with depreciation deductions, there’s a sting:
- Division 40 (plant and equipment): Depreciation claimed gets reversed — the written-down value at sale becomes the cost base for that asset, not what you originally paid
- Division 43 (capital works): Depreciation claimed reduces the building’s cost base
Those depreciation deductions you enjoyed while you owned the place? Part of them come back as a higher CGT bill when you sell. It’s not free money — it’s deferred tax.
Timing Matters
When you sell makes a real difference:
- The 12-month threshold: Own it for 12+ months and you get the 50% discount. Sell at 11 months and 29 days? Full gain, full tax.
- Income stacking: Big salary year? Had a bonus or sold another asset? Consider whether pushing settlement into the next financial year changes your bracket.
- Contract date is what counts: For CGT, the date is usually when you sign the contract — not settlement. Same idea as NZ’s bright-line test end date.
Key Takeaway
Selling at 11 months vs 13 months can mean tens of thousands in extra tax. Know your contract date and plan around it.
Australia vs NZ
| Australia | New Zealand | |
|---|---|---|
| Capital gains tax | Formal CGT regime with 50% discount after 12 months | No CGT — but bright-line test taxes gains within 2 years |
| Cost base tracking | Required — stamp duty, improvements, selling costs | Simpler — only needed if you’re within bright-line |
| Depreciation clawback | Yes — Division 40 and 43 adjustments | Minimal — limited depreciation claims |
Full side-by-side in our New Zealand vs Australia property guide.
Keep the Receipts — From Day One
CGT is calculated when you sell, but the evidence trail starts at purchase. If you can’t prove your cost base, the ATO can use a lower figure — and you cop more tax.
What you need:
- Sale and purchase contracts — buying and selling
- Settlement statements — what you actually paid/received
- Stamp duty receipts — a big cost base component (see hidden costs)
- Reno and improvement invoices — with proper descriptions of work done
- Depreciation schedules — track cumulative claims for the clawback calc
- Agent commission statement — deducted from proceeds
- Legal fee invoices — purchase and sale conveyancing
You might not sell for 10-20 years. But you need the purchase-era receipts at that point. Losing a $15,000 stamp duty receipt means a $15,000 higher taxable gain. AI document management sorts this by storing everything from day one and pulling out cost base figures automatically — ready whenever you eventually sell.
For the current Australian Taxation Office rental-property watchlist, see Australia Rental Tax Changes 2026: What the ATO Is Watching. It covers the annual deduction records that later interact with CGT cost-base and depreciation evidence.
The Short Version
- The 50% discount requires 12+ months ownership — and the gain stacks on top of your other income
- Build your cost base properly — stamp duty, legal fees, and capital improvements all count
- Depreciation clawback bumps up your CGT when you sell
- Repairs vs improvements have opposite tax effects — get the classification right
- Keep every receipt from purchase day — you’ll need them years or decades later
For a wider view of how the 12-month CGT clock fits alongside the other recurring decisions Australian landlords have to make, see What Amateur Property Investors Actually Need in Australia.
Next up: Rental Yield — The Number That Lies
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