Rental Property Calculator
Reading the numbers like an investor
Net operating income is collected rent minus operating costs, before the mortgage. Dividing it by price gives the cap rate — the property's unlevered yield. Subtracting the loan payment shows cash flow, and dividing annual cash flow by the cash you invested gives the cash-on-cash return. A property can have a decent cap rate but negative cash flow when financing is expensive, which is why both views matter.
Frequently Asked Questions
What is the one percent rule?
A quick screen suggesting monthly rent should be about 1% of the purchase price. It is rare in expensive markets, and it ignores expenses and rates — use it only as a first filter, then run the full numbers here.
How much vacancy should I assume?
A common starting point is 5–8% (roughly one vacant month every one to two years), adjusted for local demand and how quickly units re-lease in your area.