Property calculators

Property is rarely the bargain it looks like on the listing. The purchase price is only the entry ticket. Once you own the asset, you pay for it again — and again, and again — through holding costs that compound silently for as long as you hold the title. Council rates, insurance, maintenance, vacancy, management fees, depreciation, and capital costs all eat into the headline return.

These calculators are built around one premise: the most useful property number is not what you pay to buy, but what you pay each year to keep. Once you know the annual holding cost, every other property decision — buy or sell, hold or flip, rent out or live in — becomes arithmetic instead of guesswork.

All figures use 20-digit decimal precision and the property mathematics common to all jurisdictions. We avoid country-specific tax rules and ratios; instead, we let you supply the local numbers and let the engine do the long arithmetic. The result is an honest, unbranded view of property economics that no real-estate marketing brochure will give you.

The true cost of owning property

Beyond the deposit and stamp duty, property comes with a recurring cost stack that often surprises owners. Council or municipal rates, building insurance, body corporate or strata fees, water charges, maintenance, repairs, and (for landlords) management and vacancy reserves all sit on the balance sheet every year. Together these typically add 1–3% of the property value annually — for a $700,000 home, $10,000–$20,000 a year before you've made a single mortgage repayment.

The mistake most owners make is treating these costs as small line items rather than a structural fact. Over 20 years, holding costs at 2% of property value compound into the same order of magnitude as the original purchase price. The capital gain you eventually realise has to clear both the holding cost and the opportunity cost of the deposit before it counts as a return.

Use the holding-cost calculator before you make an offer, not after settlement. The number it produces is the year-one cost of ownership; it is also a reasonable proxy for what you will pay in years two, three, and four, before any maintenance compounding kicks in.

Understanding property returns

The return on an investment property has two components: rental yield and capital growth. Yield is the annualised rent the property generates as a percentage of the property's value; growth is the change in the property's market value over the holding period. Many investors fixate on growth and ignore yield, but a 2% yield gap over a decade matters as much as a 1% growth gap.

Gross yield divides annual rent by purchase price; net yield subtracts the holding cost stack and divides by the same denominator. The gap between gross and net is where most marketing materials hide — a 6% gross yield can easily become a 2% net yield once management fees, vacancy, repairs, and council rates are deducted. The rental-yield calculator computes both side-by-side so the gap is impossible to miss.

Capital growth, in turn, is not a single number but a distribution. The historical average for a metropolitan housing market is typically 3–6% per year nominal, but actual growth depends on cycle, region, and quality of the asset. A 30-year capital projection should always test multiple growth assumptions, because the difference between a 2% and a 5% assumption over three decades is enormous.

Property as an investment

Property is leveraged by design. A 20% deposit on a $700,000 property gives you 5x leverage on every percentage of capital growth — and on every percentage of decline. That leverage is the source of property's outsized historical returns and also the source of its episodic catastrophes. Modelling the asset without modelling the leverage misses the point of why investors buy property in the first place.

A useful framework is to split property returns into four parts: rent (yield), capital gain (growth), tax effects (depreciation, deductions, capital gains treatment), and leverage. Each part can be modelled separately. The depreciation calculator, for example, isolates the tax shield from physical decline of the building and fixtures — a number most amateur landlords never quantify, and one that can swing an investment from cash-flow-negative to cash-flow-neutral.

Many investors talk about "negative gearing" or "tax loss harvesting" without ever running the numbers on what their actual cash position is each year. A property losing $5,000 a year before tax may be losing $3,000 after tax — but it is still losing money. The calculators here let you see the unsubsidised number alongside the after-tax number, so the true position is unambiguous.

Selecting an investment property — a screening framework

Most property investors look at twenty listings and buy one. The discipline that separates accidental from intentional investors is screening — a sequential set of numerical filters that disqualify weak candidates before any inspection. The three filters that matter most are gross yield (rent divided by price), the holding-cost ratio (annual ownership cost divided by property value), and the opportunity-cost test (does the expected return clear the alternative use of the same capital?). Properties that fail any one of the three rarely turn into good investments regardless of how the others look.

A worked screen: a property at $700,000 with $35,000/year gross rent has a 5% gross yield. Apply a 1.5% holding-cost ratio ($10,500/year for rates, insurance, maintenance, body corporate or strata fees, vacancy, and management) and the net yield drops to roughly 3.5%. Subtract mortgage interest at, say, $25,000/year on a $560,000 loan and the property is cash-flow negative by $500/year before any tax effect. The rental-yield calculator and the holding-cost calculator produce these numbers in minutes; the screen takes longer to interpret than to compute, which is its point — most listings fail at the first or second filter.

The opportunity-cost test is the final filter and the most under-applied. The deposit tied up in a property — often $140,000 or more — could earn a return in a diversified portfolio. If the long-run real return on that portfolio is around 5%, the property must clear that hurdle in net rental yield plus expected real capital growth before it earns its place in the asset mix. A property delivering 3% net yield needs at least 2% real capital growth just to match the alternative; below that, the leverage is not compensating for the additional risk and the illiquidity. Run the rental-yield, holding-cost, and capital-gains calculators together against this hurdle before committing the deposit.

Tax implications of property ownership

Most jurisdictions tax property along several edges: a transaction tax at purchase (stamp duty, transfer duty, conveyancing tax), a recurring annual tax (council or land tax), an income tax on rent (with deductions for expenses, depreciation, and interest), and a capital gains tax on profit at sale (often with a discount for long-held assets).

The depreciation schedule is the single most under-used part of this stack for investment property. A new building's structural elements depreciate over a long life (typically 25–40 years, depending on the jurisdiction), while fixtures and fittings depreciate over a much shorter life. Combined, these can add tens of thousands of dollars in annual non-cash deductions to a landlord's tax position.

Capital gains tax on property is usually the largest single transaction in an investor's life. A long holding period, with a discount applied to long-held assets, can roughly halve the tax bill compared to an early sale. The capital-gains calculator lets you model the trade-off between selling sooner (higher tax, more reinvestment runway) and holding longer (lower tax, more capital tied up).