Capital Gains Tax Calculator

Estimate your CGT liability under the rules introduced by the 12 May 2026 federal budget. This tool models the new negative gearing restrictions, the 1 July 2027 commencement of cost-base indexation for CGT (including split treatment for assets straddling that date), the 30% minimum tax rate, and current ATO marginal rates. Not financial advice — seek a qualified tax adviser for advice on your situation.

Calculate your capital gain

Asset details

Asset class

Date of acquisition

Hypothetical sale date

Financial inputs

Cost base (purchase price + costs)

Expected sale proceeds

Annual income (before CGT)

Inflation rate (annual %) Used for indexation (post-1 Jul 2027 gains) and real-value display. Recent RBA target band: 2–3%.

How the 2026 federal budget rules work

Negative gearing — residential property only

Acquired before 7:30pm AEST 12 May 2026 — losses fully deductible against any income, retained until sale (grandfathered indefinitely).
Acquired 12 May 2026 to 30 June 2027 — losses fully deductible during this window; ring-fenced from 1 July 2027 onwards.
Acquired from 1 July 2027 — losses ring-fenced from day one: only deductible against residential rental income or property capital gains. Unused losses carry forward.
New builds — exempt from restrictions regardless of acquisition date. Full deductibility retained.
Commercial property, shares, and other asset classes are not affected by the negative gearing changes.

CGT discount — all asset classes (individuals, partnerships, trusts)

The 1 July 2027 commencement date is the key. Gains are split at this date:

Sold before 1 July 2027 — existing rules unchanged: 50% discount if held 12+ months.
Acquired and sold both after 1 July 2027 — cost-base indexation replaces the 50% discount entirely. 30% minimum effective tax rate on the gain.
Acquired before 1 July 2027 but sold after — split calculation: gains accrued up to 1 July 2027 use the 50% discount; gains accrued after 1 July 2027 use indexation. The asset's value on 1 July 2027 (market valuation or Treasury apportionment formula) is the dividing line.
New builds — investor may elect the 50% discount (across the whole gain) instead of the split/indexed method.
Pre-1985 assets — gains accrued before 1 July 2027 remain exempt. Gains accrued after 1 July 2027 are subject to indexation (cost base = value at 1 July 2027).
12-month holding rule — unchanged. Assets held under 12 months get no discount.
Main residence, small business CGT concessions, 60% affordable housing discount — unchanged.
Superannuation funds (including SMSFs) — excluded from these changes. SMSFs not modelled here.

30% minimum tax rate

Applies only to gains accruing from 1 July 2027 onwards.
Floor of 30% on the post-1-July-2027 portion of the gain.
Recipients of means-tested income support payments (e.g. Age Pension, JobSeeker) in the year of sale are exempt from the floor — not modelled here.

Tax brackets used (ATO, individual residents)

2025–26 FY: 0% / 16% / 30% / 37% / 45% at thresholds $18,200 / $45k / $135k / $190k
2026–27 FY: 0% / 15% / 30% / 37% / 45% (second-bracket cut)
2027–28 FY: 0% / 14% / 30% / 37% / 45% (further second-bracket cut)
Plus 2% Medicare levy (simplified; low-income reduction not modelled). LITO max $700 (income ≤ $37,500, tapers to $0 at $66,667).

Apportionment of gain across 1 July 2027

For assets held across 1 July 2027, the value on that date determines the split. This calculator uses Treasury's specified linear-apportionment formula by default: valueAtCGT = costBase + (saleProceeds − costBase) × (yearsHeldByCGT ÷ totalYearsHeld).
In practice, taxpayers may instead use a market valuation. ATO tools will be provided. Quoted-price assets (e.g. shares) use the actual market price on 1 July 2027.