Australian capital gains tax
50% discount vs indexed cost base CGT calculation comparison
The Australian Government will replace the 50 per cent Capital Gains Tax (CGT) discount with a discount based on inflation and introduce a minimum 30 per cent tax on gains from 1 July 2027.
Use this tool to model a property sale under both methods and see profit, cost base, taxable profit and tax side by side. The indexed method applies a minimum tax rate of 30%. Enter a flat marginal rate, or switch to other taxable income to have the gain stacked on top of your income using the FY2026-27 brackets.
Projected sale value
$1,343,136
Nominal profit
$593,136
Held for
10 years
Old method — 50% discount
Half the nominal gain, taxed at your marginal rate
- Profit
- $593,136
- Cost base
- $750,000
- Taxable profit
- $296,568
- Tax rate applied
- 47.0%
- Tax amount
- $139,387
Effective rate on gain: 23.5%
New method — indexed cost base
Cost base grown by inflation, taxed at the higher of your marginal rate and 30%
- Profit
- $593,136
- Cost base
- $1,007,937
- Taxable profit
- $335,198
- Tax rate applied
- 47.0%
- Tax amount
- $157,543
Effective rate on gain: 26.6%
The old 50% discount method results in $18,156 less tax over 10 years.
Indicative figures only. Income-based tax uses the FY2026-27 resident brackets and excludes the Medicare levy and offsets. Also excludes purchase and selling costs, stamp duty, capital improvements, ownership shares and carried-forward losses. Not tax advice.