Capital Gains Tax Calculator WA

Capital gains tax (CGT) on Western Australian property follows the same federal rules that apply across Australia — there is no separate WA CGT. When an investment property in WA is sold, the capital gain is added to the seller’s taxable income and taxed at the marginal rate (ATO — Capital gains tax overview). WA purchase costs such as transfer duty can form part of the CGT cost base and reduce the taxable capital gain. The calculator above estimates CGT for WA property sales.

How Does Capital Gains Tax Apply in WA?

CGT in Australia is a federal tax administered by the Australian Taxation Office (ATO). Western Australia does not levy a separate capital gains tax on property sales. Whether you sell a property in Perth, Mandurah, Bunbury, or regional WA, the core CGT calculation is the same: the capital gain is included in your assessable income for the financial year of sale (ATO — Capital gains tax overview).

The WA-specific part is the local purchase-cost context. WA transfer duty, conveyancing costs, and other eligible acquisition or disposal costs can change the cost base before the federal CGT calculation applies.

If you are an Australian resident individual and held the property for more than 12 months, you may be eligible for the 50% CGT discount, which halves the taxable capital gain before it is added to your income (ATO — CGT discount).

WA Transfer Duty and Your CGT Cost Base

When you buy an investment property in Western Australia, transfer duty is assessed by the Department of Treasury and Finance WA. WA applies transfer duty to dutiable transactions unless a different rate or exemption applies (Department of Treasury and Finance WA - Transfer duty assessment). Duty paid at acquisition can be included in the CGT cost base as an incidental cost of acquiring the property.

For many WA investment purchases, transfer duty is a material cost-base item. Adding it to the cost base reduces the capital gain when you later sell. If you paid no duty because of an exemption or first home owner rate outcome, there is no duty amount to include for that element.

Foreign buyers duty

Foreign buyers of WA residential property may also pay foreign buyers duty. If you paid that additional duty when buying the property, it may form part of the cost base alongside standard transfer duty (WA Government - About foreign buyers duty). The calculator has a stamp duty input where you can enter the total duty actually paid.

Division 43 deductions and the cost base

Capital works deductions can reduce the relevant capital costs included in the cost base. If you claimed Division 43 deductions while renting out the WA property, enter the total claimed amount in the calculator so the cost-base adjustment is reflected in the estimate.

Perth Property Growth and Sale-Year Tax

Perth property growth can create a substantial capital gain even when the annual holding cost has been modest. CGT is assessed in the sale year, so the same property gain can create different tax outcomes depending on your other taxable income for that year.

Selling while your salary, bonus, or business income is high can push more of the taxable gain into a higher bracket. Selling in a lower-income year can reduce the estimated tax on the gain. The calculator lets you adjust your other income to test those sale-year scenarios.

WA-Specific Worked Example

Assume the following scenario for a Perth investment property:

• Purchase price: $650,000
• WA transfer duty paid: $24,890
• Legal fees (purchase): $2,500
• Capital improvements: $15,000
• Div 43 deductions claimed: $5,000
• Sale price: $820,000
• Agent commission: $16,400
• Legal fees (sale): $1,800
• Holding period: 5 years (eligible for 50% discount)
• Other income in the sale year: $88,000

Step 1: Calculate the cost base

Step 2: Calculate the capital gain

Capital gain = Sale price - Cost base

$820,000 - $705,590 = $114,410

Step 3: Apply the 50% CGT discount

Because the property was held for 5 years (more than 12 months):

Taxable capital gain = $114,410 x 50% = $57,205

Step 4: Calculate estimated CGT

The $57,205 taxable gain is added to $88,000 other income, giving total taxable income of $145,205. Based on the calculator’s 2025-26 resident tax settings, the estimated additional tax on the gain is approximately $19,000.

Without the 50% discount, the full $114,410 would be taxable and the estimated CGT would be approximately $42,300 — the discount saves roughly $23,300 in this scenario.

Including the $24,890 WA transfer duty in the cost base reduces the capital gain from $139,300 to $114,410. After the discount and income-tax calculation, that reduces the estimated CGT by approximately $4,850 in this scenario.

Related WA Property Calculators

• Land Tax Calculator — estimate WA land tax or compare Western Australia with other Australian states.
• Negative Gearing Calculator — estimate the tax effect and after-tax cash flow of a WA investment property.
• Rental Yield Calculator — compare gross and net rental yield before modelling a sale.
• Investment Property Calculator — combine cash flow, land tax, yield, and CGT into one property scenario.