Property Investment Calculator Australia: The Numbers Every Investor Needs to Run Before They Buy

Before you make an offer on any investment property, there are five calculations you need to run. Not one. Not three. Five — and they build on each other. Most investors run one or two, convince themselves the numbers work, and proceed. The ones who build serious portfolio wealth run all five and understand exactly what they are committing to.

This guide walks through each calculation with real worked examples at typical 2026 Australian values. You will not need a spreadsheet or special software — a phone calculator is enough. What you need is to understand what each number actually means.

Gross rental yield is the starting point. It tells you the annual rental income as a percentage of the purchase price — before any expenses. It lets you compare properties on an apples-to-apples basis and tells you quickly whether a property is a yield play, a growth play, or neither.

Formula: (Annual Rent ÷ Purchase Price) × 100 = Gross Yield %

Worked example:
Purchase price: $750,000
Weekly rent: $580
Annual rent: $580 × 52 = $30,160
Gross yield: ($30,160 ÷ $750,000) × 100 = 4.02%

What the numbers mean in 2026:
Below 3%: Low yield. Acceptable only if strong capital growth is expected and you can carry the cash flow.
3% to 4%: Typical for major capital city residential in growth suburbs. This is the range most negatively geared properties sit in.
4% to 5%: Better balance of yield and growth. Common in outer metro and some regional markets.
Above 5%: High yield. Typically signals lower capital growth expectations or a higher-risk market.

The limitation: Gross yield ignores all expenses. It is useful for quick comparisons but does not tell you the actual cost or return of ownership.

Net rental yield accounts for all the costs of ownership, giving you a realistic picture of actual income relative to what you paid.

Formula: ((Annual Rent - Annual Expenses) ÷ Purchase Price) × 100 = Net Yield %

Annual expenses to include:
Property management fee (typically 8-9% of gross rent including GST): ~$2,715
Council rates: ~$1,800
Water rates: ~$900
Landlord insurance: ~$1,400
Maintenance and repairs allowance (1% of property value per year is a conservative benchmark): ~$7,500
Body corporate / strata levy (if applicable): varies
Property management letting fee allowance (amortised over average 12-month tenancy): ~$560
Total annual expenses (excluding loan interest and depreciation): approximately $14,875

Continuing the worked example:
Annual rent: $30,160
Annual expenses (ex-interest, ex-depreciation): $14,875
Net income before interest: $30,160 - $14,875 = $15,285
Net yield before interest: ($15,285 ÷ $750,000) × 100 = 2.04%

The gap between 4.02% gross and 2.04% net before interest illustrates why gross yield is misleading as a decision metric. The real income is roughly half the headline number.

Net yield after interest (the true cash flow position):
Loan: $600,000 (80% LVR) at 6.8% interest-only = $40,800/year
Net income before interest: $15,285
Annual shortfall (pre-tax): $40,800 - $15,285 = $25,515
This is the property as a negative gearing candidate — generating a $25,515 annual tax loss.

The negative gearing calculation turns the annual shortfall into an after-tax cost by accounting for the tax refund the ATO returns to you. This is the number most investors misunderstand — they think about the gross cash outflow without accounting for the government contribution.

What to add to the shortfall: Depreciation (non-cash deduction) increases the total tax loss beyond the cash shortfall. A quantity surveyor depreciation schedule on a 2010-built property at $750,000 might generate $8,000/year in Division 43 capital works deductions.

Worked example:
Cash shortfall: $25,515
Depreciation (non-cash): $8,000
Total tax loss: $33,515
Tax refund at 47% marginal rate: $33,515 × 0.47 = $15,752
Real after-tax annual cost: $25,515 - $15,752 = $9,763/year or $188/week

The property that appears to cost $491/week in cash actually costs $188/week after the ATO returns its share. This is the correct number to use when assessing whether you can afford to hold it.

At different marginal rates:
34.5% (income $45K-$135K): Tax refund = $11,563. After-tax cost = $13,952/year ($268/week).
39% (income $135K-$190K): Tax refund = $13,071. After-tax cost = $12,444/year ($239/week).
47% (income $190K+): Tax refund = $15,752. After-tax cost = $9,763/year ($188/week).

This illustrates why negative gearing is more valuable at higher incomes. The ATO subsidy scales with the marginal rate. For the step-by-step calculation with your specific numbers: negative gearing calculator Australia. For the complete guide: negative gearing Australia: the complete guide.

Total return combines rental income and capital growth to produce the actual investment return. This is the number that justifies — or fails to justify — the after-tax carrying cost.

Formula: Total Return = Capital Growth + Net Rental Income (after tax effects)
As a percentage: Total Return % = (Capital Growth $ + Net Rental Income $) ÷ Equity Invested × 100

Worked example over 10 years:
Purchase price: $750,000
Deposit (20%): $150,000
Capital growth at 6.5% per year for 10 years: $750,000 × (1.065^10 - 1) = $659,380
Total after-tax cost over 10 years at 47% marginal rate: $9,763 × 10 = $97,630
Net wealth created: $659,380 - $97,630 = $561,750
Return on $150,000 initial equity: $561,750 ÷ $150,000 = 374% total return over 10 years

At 4% capital growth (more conservative, softer market):
Capital growth: $750,000 × (1.04^10 - 1) = $360,188
Net wealth: $360,188 - $97,630 = $262,558
Return on equity: $262,558 ÷ $150,000 = 175% total return over 10 years

At 2% capital growth (flat market):
Capital growth: $750,000 × (1.02^10 - 1) = $164,999
Net wealth: $164,999 - $97,630 = $67,369
Return on equity: $67,369 ÷ $150,000 = 45% total return over 10 years

This range illustrates the critical importance of market selection. The property must be in a market where 6%+ long-run growth is realistic for the leverage effect to produce the returns that justify the investment. A flat-market property with a positive yield may produce a similar total return to a negatively geared property in a growth market, but neither approach works in a declining market. For market selection: best suburbs to invest in Australia 2026.

Most investors calculate forward-looking returns without accounting for the tax payable when they sell. This is the calculation that most often produces a nasty surprise when it is too late to do anything about it.

Formula (2026 rules):
Sale price - Cost base = Gross capital gain
Gross gain × 0.67 (33% discount for properties held 12+ months) = Assessable gain
Assessable gain × Marginal rate = CGT payable

Cost base components (do not underestimate this):
Purchase price: $750,000
Stamp duty (NSW): ~$27,000
Legal and conveyancing: ~$2,500
Depreciation claimed over 10 years (reduces cost base): -$80,000
Capital improvements during ownership: +$30,000
Selling costs (agent, legal, marketing): ~$25,000
Net cost base: $750,000 + $27,000 + $2,500 - $80,000 + $30,000 + $25,000 = $754,500

CGT calculation at 10-year sale at 6.5% growth:
Sale price: $1,409,380
Cost base: $754,500
Gross gain: $654,880
Assessable gain (after 33% discount): $654,880 × 0.67 = $438,770
CGT at 47% marginal rate: $438,770 × 0.47 = $206,222

The CGT represents 31% of the total gross gain. After CGT, net wealth created: $659,380 - $97,630 (holding costs) - $206,222 (CGT) = $355,528 from a $150,000 deposit — still 237% return over 10 years.

The SMSF pension phase comparison: The same property held inside an SMSF and sold in pension phase: CGT = $0. Net wealth created: $659,380 - $97,630 = $561,750. Difference: $206,222 in additional wealth from the structure alone. For the complete CGT strategies: CGT on investment property: the complete guide. For SMSF: SMSF property investment: the complete 2026 guide.

Before making an offer on any property, confirm you have calculated:

1. Gross yield: Is it above 3%? Below 3% requires exceptional growth prospects to justify.
2. Net yield after all costs (ex-interest): What is the actual income? What is the annual cash shortfall before the tax effect?
3. After-tax carrying cost: After negative gearing tax refund and depreciation, what does this property actually cost per week? Can you sustain this for 12 months if it is vacant?
4. Total return at 3 growth scenarios: Run it at 3%, 6%, and 8% annual growth. At what growth rate does the investment fail to justify itself?
5. CGT on exit: At your intended exit point, what is the tax bill? Have you factored this into your total return? Is there a structure (SMSF pension phase, low-income year, main residence exemption) that reduces it?

If any of these five calculations produces an unacceptable number, that is information — not a reason to panic, but a reason to reconsider the price, the market, or the structure before committing.

Before running the five calculations above on any specific property, check your borrowing capacity. There is no point modelling a $900,000 property if you can only borrow $550,000.

Quick borrowing capacity estimate:
Take your gross annual income. Multiply by 4 to 5 (conservative) or 5 to 6 (including rental income credit). Subtract all existing debt (outstanding loan balances, not repayments). The result is a rough maximum borrowing capacity. It is not accurate enough to rely on for an offer — get a pre-approval — but it tells you the right price range to target.

Example:
Gross income: $150,000
Conservative multiplier: $150,000 × 5 = $750,000 maximum loan
Minus existing home loan: $400,000
Available for investment loan: approximately $350,000
At 80% LVR: can buy a property up to $437,500

For the full borrowing capacity breakdown including how lenders shade rental income, apply the serviceability buffer, and assess multiple properties: investment property loans 2026: what you can borrow.

Book a Strategy Call
If you want these calculations run specifically for your income, deposit, target market, and retirement timeline — a 20-minute call with our team will give you the actual numbers.
https://www.ausretirementoffice.com.au/book

Disclaimer: The information provided by Australian Retirement Office is general in nature and educational only. It does not constitute financial product advice, legal advice, or taxation advice. All worked examples are illustrative only and use assumed values. Australian Retirement Office does not hold an AFSL. All investments carry risk. Past performance is not a reliable indicator of future returns. Obtain professional advice before making financial decisions.

Related: Negative Gearing Calculator | Negative Gearing: Complete Guide | CGT: Complete Guide | Property Investment: Complete Guide | Investment Property Loans 2026 | SMSF Property: Complete Guide