Rental Property Calculator

Buying a rental property is ultimately a cash-flow decision: does the rent, after every cost, leave money in your pocket each month? This calculator answers that by bringing together the three numbers serious investors live by — monthly cash flow, cash-on-cash return, and cap rate.

Monthly cash flow is the headline. It's your effective rent (rent minus a vacancy allowance) minus your operating expenses (taxes, insurance, maintenance, management) minus your mortgage payment. Positive cash flow means the property pays you every month; negative means you're feeding it. Many beginners forget that the mortgage and expenses can easily swallow the rent, so seeing the real figure before you buy is essential.

Cash-on-cash return is the metric that tells you how hard your money is working. It divides your annual cash flow by the actual cash you invested — primarily your down payment. A property might have modest total returns but a strong cash-on-cash figure because leverage (the mortgage) lets a relatively small amount of your own money control a large asset. This is why cash-on-cash, not cap rate, is the number most buy-and-hold investors optimize for: it reflects your real return on the cash at risk.

The calculator also shows the cap rate (the unleveraged return on the full price) for comparison, since the two metrics tell you different things — cap rate compares properties on equal footing, while cash-on-cash reflects your specific deal with its specific financing.

A few cautions. The figures are estimates only as accurate as your inputs, so be realistic about expenses — new investors routinely underestimate maintenance, vacancy and management costs. Cash flow also isn't the whole return: appreciation, loan paydown (your tenants building your equity) and tax benefits all add to the picture but aren't captured here. Use the calculator to screen deals quickly and avoid obvious money-losers, then dig deeper on the ones that pencil out. A property with healthy positive cash flow and a solid cash-on-cash return is the foundation of a sound rental investment.