Cash Flow Calculator for Australian Property Investors

Cash flow is simply the money left over after the rent has paid all the costs of holding a property. Positive cash flow means the rent more than covers your mortgage repayments and expenses, so the property puts cash in your pocket each week. Negative cash flow means the costs are higher than the rent, so you top it up from your own income.

This calculator gives you the before-tax cash flow, which is the figure that actually moves through your bank account. It is the cleanest way to see whether a property pays its own way before you layer on tax considerations like depreciation or negative gearing.

A positively geared property earns more in rent than it costs to hold, so it generates income. That income is added to your taxable earnings, but the property funds itself and eases the pressure on your household budget. A negatively geared property costs more to hold than it earns, creating a shortfall you cover yourself.

Neither is automatically better. Negatively geared properties are common in Australia, particularly in higher-growth city markets where rents are low relative to prices, and the shortfall may be partly offset at tax time. Positive cash flow properties are easier to hold and scale but can come with slower growth. The right mix depends on your income, your goals and how much shortfall you can comfortably fund.

It is easy to look at the rent and the mortgage and assume the gap between them is your cash flow. In reality, the smaller costs add up: council and water rates, landlord insurance, property management, strata, and the weeks the property sits empty between tenants all chip away at the result.

Building vacancy into the calculation is important because no property earns rent every single week of the year. Allowing for a week or two of vacancy, plus realistic figures for each expense, gives you a number you can actually rely on rather than a best-case guess.

Cash flow tells you what a property costs to hold, but not what it earns you overall. Two other forces matter just as much: capital growth, which is the increase in the property's value over time, and the tax treatment of any rental loss. A property that costs you a little each week can still be a strong investment if it is growing in value faster than it costs to hold.

Because this is a before-tax estimate, it does not include depreciation, the tax saving from negative gearing, or future rent rises. Treat the result as a starting point, and confirm your full position with a qualified accountant or financial adviser before you commit.