CGT Calculator — old 50% discount vs new inflation method
See what the Federal Budget 2026 capital gains tax reforms cost you. Today's 50% discount on one side, the new inflation indexation method (with a 30% minimum tax) on the other. Coming 1 July 2027 for new investments.
What you bought it for, including stamp duty + acquisition costs
What you'd sell it for
Agent fees, legal, conveyancing
2.5% is the RBA target band midpoint
You'd pay $36,984 more tax under the new rules — a 42% increase.
Today's rules
50% discount, until 30 Jun 2027
Tax owed
$88,800
From 1 Jul 2027
Inflation method + 30% floor
Tax owed
$125,784
Your marginal rate is above 30%, so the 30% floor on the real gain doesn't bind — you just pay your marginal rate on the indexed real gain.
Want to see how this affects your whole financial picture — your assets, super, retirement plan?
Try the full planDisclaimer: This calculator provides estimates for general information purposes only. Results may not be 100% accurate and should not be relied upon for financial decisions. Tax rules, rates, and thresholds change — always verify with the ATO, official government sources, or a qualified financial adviser, tax professional, or accountant. This is not financial advice.
What's actually changing?
Since 1999, individuals selling an asset they've held for at least 12 months have received a 50% CGT discount — only half the gain is added to taxable income, then taxed at the marginal rate.
From 1 July 2027, that discount is replaced with an inflation indexation method: the cost base is uplifted by inflation across the holding period, and only the “real” gain is taxed at the marginal rate. A 30% minimum tax on the real gainapplies as a floor — but only if your marginal rate is below 30%. For most investors at 30%+ marginal rates, the floor doesn't bind and you simply pay your marginal rate on the indexed real gain.
The reform is intended to tax the real gain, not the inflation-driven part of it. Despite the indexation relief, the new method still produces a higher tax bill than today's 50% discount in most long-hold scenarios — the discount was simply more generous than indexation at typical inflation rates.
Grandfathering — do these rules apply to my assets?
The new rules apply to gains arising after 1 July 2027 on assets acquired after 7:30pm AEST on 12 May 2026 (Budget night). Anything you owned before 12 May 2026 stays on today's 50% discount rules permanently.
Investors in new builds can choose either method. This calculator does not model the new-builds election.
The math behind the calculator
Nominal gain = Sale price − Purchase price − Selling costs.
Today's rules: if you held the asset for at least 12 months, taxable gain = nominal gain × 50%, then taxed at your marginal rate.
New rules (from 1 July 2027):
- Indexed cost base = Purchase × (1 + inflation rate) ^ years held
- Real gain = Sale − Indexed cost base − Selling costs
- Marginal-rate tax = Real gain × your marginal rate
- 30% floor = Real gain × 30% (only binds if your marginal rate is below 30%)
- Tax owed = the higher of the two
What this calculator does not include
- Your other taxable income for the year (we use a flat marginal rate you pick)
- The pensioner / income-support exemption from the 30% floor (you can ignore the floor entirely if you're on income support)
- Capital improvements added to the cost base after purchase
- Partial-year ownership, deceased estate transfers, or CGT events other than disposal
- Negative gearing changes (those reform the deductibility of holding losses, not CGT)
- State-specific stamp duty refunds or first-home concessions
For a full picture of how a property sale flows through your tax, super, and retirement plan, try the JettWorth play mode — no sign-up required.
Important: this is not financial advice
JettWorth is an insights platform, not a licensed financial adviser. Numbers shown here are projections based on the assumptions you enter and the policy as announced — final legislation may differ. Always consult a qualified financial adviser, accountant, or tax professional before acting on what you see here.