Australian capital gains tax

50% discount vs indexed cost base

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%. The tool does not yet account for profits that cover multiple tax brackets; it performs a simple calculation based on the tax rate provided.

AUD
%
%
%
yrs
1 year50 years

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

Lower tax
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.

Old methodNew method
Profit$593,136$593,136
Cost base$750,000$1,007,937
Taxable profit$296,568$335,198
Tax amount$139,387$157,543

Indicative figures only. Excludes purchase and selling costs, stamp duty, capital improvements, ownership shares, carried-forward losses and the Medicare levy. Not tax advice.