CGT Projection Calculator Australia — Individual, SMSF, Company

CGT projection is one of the most decision-relevant numbers for property investors before they sell. The discount eligibility and the ownership structure together can make a 30–40% difference in tax owed on the same nominal gain. This calculator handles the four main ownership types — individual, SMSF accumulation, SMSF pension, company — with the correct discount rate per type and the 12-month threshold for the discount.

How CGT is calculated

Cost base       = purchase price + purchase costs + capital improvements
Capital proceeds = sale price − sale costs
Capital gain    = capital proceeds − cost base

Discount        = 50% (individual, held ≥ 12 months)
                = 33⅓% (SMSF accumulation, held ≥ 12 months)
                = 0% (held < 12 months, or company)

Taxable gain   = capital gain × (1 − discount)
Tax owed       = taxable gain × tax rate
After-tax proceeds = capital proceeds − tax owed

Tax rate by ownership type:

• Individuals — your marginal income tax rate (16% / 30% / 37% / 45%) applied to the taxable gain
• SMSF accumulation — 15% applied to the discounted taxable gain
• SMSF pension — exempt; tax owed is $0
• Companies — 30% applied to the full gain (no discount available)

The 12-month rule

The biggest planning lever for individuals: timing the sale to be at least 12 months after purchase.

A $200,000 gain held 11 months → $200,000 taxable at 37% = $74,000 tax. The same gain held 13 months → $100,000 taxable at 37% = $37,000 tax.

That's $37,000 of pure timing arbitrage. The 12-month period runs from contract-of-purchase date to contract-of-sale date — settlement dates don't count for this purpose.

Worked example: individual investor

Purchase: $600,000 with $30,000 of acquisition costs in early 2021 Sale: $800,000 with $25,000 of selling costs in late 2024 (≈3 years held) Investor's marginal rate: 37%

Element	Value
Cost base	$630,000
Capital proceeds	$775,000
Capital gain	$145,000
50% discount	$72,500
Taxable gain	$72,500
Tax owed @ 37%	$26,825
After-tax proceeds	$748,175

Without the 50% discount (e.g. held only 11 months) the tax owed would be $53,650 — almost double.

Worked example: SMSF accumulation

Same property, same dates, but held in an SMSF accumulation account:

Element	Value
Cost base	$630,000
Capital proceeds	$775,000
Capital gain	$145,000
33⅓% discount	$48,333
Taxable gain	$96,667
Tax owed @ 15%	$14,500
After-tax proceeds	$760,500

SMSF accumulation pays significantly less CGT than a 37%-bracket individual on the same gain — $14,500 vs $26,825. That's the structural advantage of holding investment property in super.

Worked example: SMSF pension

Same scenario, but the SMSF is in pension phase at the time of sale: $0 tax owed. The capital proceeds flow into the fund untaxed and are paid out as tax-free pension. This is why members typically wait until pension phase before realising large CGT events.

Worked example: company ownership

Same scenario, held in a company:

Element	Value
Capital gain	$145,000
Discount	$0 (none for companies)
Taxable gain	$145,000
Tax owed @ 30%	$43,500

Companies pay the most CGT on this gain (no discount). They make sense for active business ownership of property (operating premises, etc.) but rarely for passive investment.

Main residence (PPR) exemption

If the property was your principal place of residence for the entire holding period, the gain is fully exempt — toggle this on and the calculator returns zero tax owed.

Common nuances NOT modelled in this calculator:

• Partial PPR: lived in for some of the hold, rented for the rest. Apportioned exemption applies.
• Six-year absence rule: moved out, rented for up to 6 years, sold. May still qualify for full exemption if elected.
• Two-residence concurrent: only one property can be a main residence at a time, with limited overlap during change of residence.

For these cases, work with a registered tax agent — the partial calculations involve apportioning by days of use and are too case-specific for a generic calculator.

Why this matters for buyers agents

Investment strategy decisions hinge on after-tax outcomes. A property growing at 7% pa over 7 years can produce wildly different after-tax returns depending on:

• Holding individually at 45% top marginal rate
• Holding individually at 30% rate
• Holding in SMSF accumulation
• Holding via a discretionary trust with adult-beneficiary distributions
• Holding in a company

The calculator handles the four main ownership types so an agent can show a client what their realistic after-tax outcome looks like under each structure, without needing a tax agent in the meeting.

What this calculator does not cover

• Trust ownership and beneficiary distributions
• Indexation method for assets purchased before 21 September 1999
• Loss carry-forward against current-year gains
• Medicare levy (small additive effect for most individuals)
• Partial main residence exemption
• Six-year absence rule
• Deceased estate cost base step-up
• CGT events other than disposal (E.g. CGT events C2, F1)

For any of these, talk to a registered tax agent. This calculator is a planning tool for the standard cases.