If you make a $100,000 capital gain in Australia — from selling an investment property, shares, or other CGT asset — the tax you pay depends on your other taxable income, whether you held the asset for more than 12 months, and whether any cost base deductions apply. In 2026, a $100,000 capital gain can result in anywhere from $0 to $45,000+ in additional tax depending on your circumstances. Here is exactly how the calculation works.

The 50% CGT Discount: The Most Important Variable

If you held the asset for more than 12 months before the disposal (selling date), you are entitled to the 50% CGT discount. This reduces your taxable capital gain from $100,000 to $50,000 — halving the tax you pay. The discount is available to individuals and trusts (not companies). Foreign residents cannot access the discount on gains accrued after May 2012.

Tax Calculation: $100,000 Gain, Held Under 12 Months

Without the 50% discount, the full $100,000 gain is added to your other taxable income and taxed at your marginal rate:

  • Income of $80,000 + $100,000 gain = $180,000 total — the $100,000 is split across the 32.5% and 37% brackets, resulting in approximately $35,000-$37,000 in additional tax
  • Income of $50,000 + $100,000 gain = $150,000 total — gain is taxed across 32.5% and 37% brackets, approximately $32,000-$35,000 in additional tax
  • Income of $130,000 + $100,000 gain = $230,000 total — gain is entirely in the 45% bracket, approximately $45,000 in additional tax

Tax Calculation: $100,000 Gain, Held Over 12 Months

With the 50% discount, only $50,000 is added to your taxable income:

  • Income of $80,000 + $50,000 discounted gain = $130,000 total — additional tax of approximately $16,250-$17,500
  • Income of $50,000 + $50,000 discounted gain = $100,000 total — additional tax of approximately $15,000-$16,000
  • Income of $190,000 + $50,000 discounted gain = $240,000 total — additional tax of approximately $22,500 (at 45%)

Capital Losses Can Reduce Your Gain

If you have capital losses from the same year or carried forward from prior years, these reduce your capital gain before the 50% discount is applied. For example, if you have a $100,000 gain and a $30,000 capital loss, your net gain is $70,000 — then the 50% discount applies (if held 12+ months), leaving $35,000 to add to your taxable income. Strategic use of capital losses is one of the most effective CGT reduction tools.

Frequently Asked Questions

How do I calculate my capital gain on a property sale?

Capital gain = Sale price minus cost base. The cost base includes: the original purchase price, stamp duty, legal costs on purchase, improvement costs (renovations, extensions), and selling costs (agent commission, legal fees on sale). You do not deduct previous depreciation claims from the cost base (though you must add back Building and Plant depreciation previously claimed for investment properties — this is called the depreciation recapture rule).

Do I pay CGT on my family home?

Generally no. Your principal place of residence is exempt from CGT under the main residence exemption, provided you lived in it for the entire period of ownership and it was not used to produce income. Partial exemptions apply if you rented part of the property, rented it out for a period, or the property exceeds 2 hectares. Moving overseas and renting your former home can also partially reduce the exemption.

Have a significant capital gain in 2025-26? Contact AWTS — we help clients minimise CGT through timing strategies, loss harvesting, and correct application of the 50% discount.