Investment Property Cash Flow Calculator

1,800 rent minus 950 mortgage, 150 management, 120 maintenance, 80 insurance = 500 monthly cashflow. Positive cashflow is the goal — negative is speculation on appreciation. Account for vacancy (typically 5-8% per year) in your expectations.

Run it with sensible defaults

Using monthly rent of 1,800, monthly mortgage of 950, monthly management of 150, monthly maintenance of 120, the calculation works out to 500.00. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Monthly Rent, Monthly Mortgage, Monthly Management, Monthly Maintenance, and Monthly Insurance — do not pull with equal force. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

How the math works

Rent minus all monthly costs.

Why investors run this

Most people's intuition for compounding is wrong — not because the math is hard, but because linear thinking doesn't account for curves. Running numbers through a calculator like this one is the cheapest way to recalibrate that intuition before making an irreversible decision about contribution rate, asset mix, or retirement age.

What this doesn't capture

Steady-rate math ignores real-world volatility. Actual returns are lumpy; sequence-of-returns risk matters most in drawdown; fees and taxes drag on compound growth; and behaviour changes in drawdowns can reduce outcomes below the projection. The number represents one scenario rather than a forecast.

Worked example

A property generates 2,200 per month in rent. The owner pays 1,050 in mortgage, 180 in property management, 160 in maintenance reserves, and 95 in insurance. The calculation shows:

2,200 − 1,050 − 180 − 160 − 95 = 715 monthly net cash flow

Annualised, this property produces 8,580 in net cash flow across twelve months. If the owner sets aside an additional 10% of rent as a contingency for unexpected repairs or vacancy periods, the effective monthly cash flow tightens to approximately 615.

When this calculation matters

Property investors use monthly cash flow estimates in several contexts:

• Comparing two or more properties before purchase to identify which generates stronger positive cash flow relative to capital deployed
• Planning for debt service and operating expense coverage when rental income fluctuates seasonally
• Stress-testing assumptions about rent, maintenance costs, or insurance premiums to model downside scenarios
• Distinguishing between properties held for current income and those held for long-term appreciation
• Understanding the gap between gross rent and net usable cash available for reinvestment or personal use

What the result captures and does not

The calculator shows estimated monthly cash flow based on the inputs provided. It does reflect the straightforward arithmetic of rent minus direct operating costs. It does not include:

• Capital gains, depreciation, or tax treatment of rental income
• Vacancy rates, tenant turnover, or collection losses (though these can be modeled by reducing rent)
• Major capital expenditures such as roof replacement, HVAC overhaul, or structural repairs
• Financing changes if the loan rate adjusts, term shortens, or the property refinances
• Market rental growth or expense inflation over time
• Financing costs beyond the monthly mortgage payment

This tool illustrates cash flow under stated assumptions. Actual monthly results depend on tenant behaviour, market conditions, and unplanned maintenance events.