A rental property calculator is how smart landlords turn a listing into a decision. A property's price tag tells you almost nothing — what matters is the gap between the rent it can earn and everything it costs to own. This free tool runs that full picture in seconds: monthly cash flow, net operating income, cap rate, and cash-on-cash return.
Cap rate is the universal yardstick of real estate investing. It divides the property's net operating income (rent minus operating expenses, before the mortgage) by the purchase price, giving you a financing-free measure of how hard the asset works. Investors compare cap rates across neighborhoods the way shoppers compare price tags — a 7% cap rate on a $300,000 duplex earns $21,000 a year before debt payments.
Cash-on-cash return answers the more personal question: what return does your money earn? Because rental investing is almost always leveraged, a 6% cap rate can become a 10%+ cash-on-cash return when the mortgage is cheap — or collapse to zero when the payment eats the entire profit. This calculator shows both, side by side, so you see the property and your financing as separate decisions.
How to use the Rental Property Calculator
- Enter the purchase price and monthly rent — use the actual listed rent or a realistic market rent for the area.
- Add your financing: down payment, closing costs, interest rate, and loan term. The calculator amortizes the loan exactly like a lender does.
- Fill in the carrying costs: annual property tax and insurance, monthly HOA dues, and any other recurring expenses.
- Set your reserves: vacancy, maintenance, and management as percentages of rent. Start with 5%, 8%, and 8% and adjust for the property's age and your market.
- Click Analyze property — then change the rent or expenses to stress-test best- and worst-case scenarios.
Tips for accurate results
- Verify the rent against comparable listings — never trust a seller's optimistic rent projection without checking.
- Never budget zero for maintenance or vacancy. Even great properties need roofs, appliances, and months between tenants.
- Self-managing? Still budget the management percentage — it represents your time, and makes properties comparable if you ever hire help.
- The classic 1% rule (monthly rent ≈ 1% of price) is a quick screen, but this calculator replaces it with real numbers.
What makes a rental property profitable?
Positive monthly cash flow is the foundation: after the mortgage, taxes, insurance, maintenance, vacancy, and management, there should be money left over — not just break-even. Beyond that, watch the cap rate (compare it to similar properties in the same city), the cash-on-cash return (your reward for the down payment you locked up), and the total cash invested. Strong deals usually combine all three: decent cap rate, double-digit cash-on-cash, and a cash reserve buffer for the inevitable surprise repair.
Frequently asked questions
What is a good cap rate for a rental property?
A cap rate between 5% and 10% is typical for residential rentals in the US. Higher cap rates usually mean higher returns but also higher risk — Class C or D neighborhoods, older buildings, or volatile markets. Prime Class A areas often run 3–5%. The right target depends on your market, risk tolerance, and financing.
What is the difference between cap rate and cash-on-cash return?
Cap rate is the property's net operating income divided by its price — it ignores financing, so it measures the asset itself. Cash-on-cash return divides annual cash flow by the cash you actually invested (down payment plus closing costs) — it reflects your return on your own money after the mortgage. Investors use cap rate to compare properties and cash-on-cash to judge how their financing affects returns.
How do I estimate maintenance and vacancy costs?
Common rules of thumb: budget 5–10% of rent for maintenance (higher for older properties), 5–10% for vacancy (higher in slow markets), and 8–12% for professional property management. These are placeholders, not substitutes — adjust them to match your local market and the property's condition.
Does this calculator include appreciation and tax benefits?
No — this tool measures operating performance only: rent minus expenses and mortgage payments. It does not model price appreciation, tax deductions, depreciation, or principal paydown, all of which add to a landlord's total return. Treat these figures as your cash-flow picture, not your total wealth picture.