Deciding whether a rental property is worth buying comes down to a few numbers that translate rent and expenses into return. Two of the most important are the capitalization rate and cash-on-cash return. Learning to calculate them lets you compare very different properties on an apples-to-apples basis.
Net operating income comes first
Every rental metric starts with net operating income, or NOI, which is annual rental income minus operating expenses. Operating expenses include taxes, insurance, maintenance, management, and a vacancy allowance, but importantly they exclude mortgage payments. NOI measures the income the property itself produces, independent of how you finance it. Getting NOI right, with honest expense estimates, is the foundation for every ratio that follows.
Cap rate: valuing the property itself
The capitalization rate is NOI divided by the property's price or value, expressed as a percentage. A property with 15,000 dollars of NOI and a 250,000 dollar price has a 6 percent cap rate. Because it ignores financing, cap rate lets you compare properties and gauge how a market prices income. Higher cap rates suggest more income per dollar of price but often come with higher risk or less desirable locations.
Cash-on-cash: the return on your cash
Cap rate ignores your loan, but as a buyer you care about the return on the actual cash you invest. Cash-on-cash return divides your annual pre-tax cash flow, after the mortgage, by the total cash you put in for the down payment and closing costs. Because leverage lets a modest down payment control a large asset, cash-on-cash can be higher or lower than the cap rate depending on your loan terms. It answers the practical question of what your invested dollars actually earn.
Using the metrics without being fooled
These ratios are only as honest as the assumptions behind them. Listings often quote optimistic rents and skip vacancy, maintenance, and management, which inflates NOI and every metric built on it. Always stress-test the numbers with realistic expenses and a vacancy allowance before trusting a cap rate. The metrics guide the decision, but conservative inputs are what keep you from overpaying.
A property costs 250,000 dollars and produces 15,000 dollars of NOI, a 6 percent cap rate. You put 62,500 dollars down and, after the mortgage, net 4,000 dollars of cash flow a year, giving a cash-on-cash return of about 6.4 percent on your invested cash.
Key takeaways
- NOI is annual income minus operating expenses and excludes the mortgage.
- Cap rate equals NOI divided by price and compares properties regardless of financing.
- Cash-on-cash return measures pre-tax cash flow against the cash you actually invest.
- Optimistic expense assumptions inflate every metric, so use conservative inputs.
Common mistakes
- Including the mortgage payment in NOI, which distorts the cap rate.
- Trusting a listing's rosy rent and expense figures without checking them.
- Comparing properties on cap rate alone while ignoring condition and location risk.
FAQ
What is a good cap rate?
It depends on the market and risk. Lower cap rates often reflect safer, high-demand areas, while higher ones can signal more risk or upside, so there is no single right number.
Why does cash-on-cash differ from cap rate?
Cap rate ignores financing, while cash-on-cash reflects your loan and down payment, so leverage and interest costs push the two apart.