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Rental Property Calculator
Cash flow, cap rate and ROI on any rental.
By Jessica Martinez · Real Estate Finance Editor · Updated June 2026Cash flow, cap rate and ROI on any rental.
By Jessica Martinez · Real Estate Finance Editor · Updated June 2026Estimate for planning. Not financial advice.
Start with effective rent: monthly rent minus the vacancy percentage. Subtract the mortgage payment, taxes, insurance, HOA, maintenance and a management fee sized off effective rent, and what is left is monthly cash flow. Multiply by twelve for the annual figure. Net operating income, which strips out the mortgage entirely, is what drives cap rate. Cash-on-cash divides annual cash flow by the money you actually put down, and total ROI folds in the principal you pay down each year on top of that cash flow.
Plug in a $350,000 purchase with 25% down, a 7% rate over 30 years and $2,600 in monthly rent, and this calculator lands on a monthly cash flow of about negative $232, a 5.19% cap rate, a cash-on-cash return of negative 3.19%, and a total ROI near 20.76% once principal paydown is folded in. That negative cash flow with a positive total ROI is a common pattern on a fresh purchase at 7% financing: the deal is not throwing off spendable cash yet, but the tenant is still paying down the loan and building equity for the owner every month.
Taxes, escrow, closing costs and refinance math all live in the calculator library below.
Cash flow is what hits your pocket each month after every expense, including the mortgage. Cap rate ignores financing and shows a property's raw earning power (net operating income over price), which is useful for comparing deals side by side regardless of how each buyer financed the purchase. Cash-on-cash measures return on the actual cash you invested, and it is the number most buyers care about because it reflects their real out-of-pocket exposure. Total ROI adds in the principal you pay down each year, which is real equity even when monthly cash flow is thin or negative.
The fastest way to fool yourself on a rental is to forget vacancy, maintenance and management fees. A property that looks like it cash flows on a napkin can bleed money the month a tenant leaves or the roof needs replacing. This calculator bakes a vacancy allowance, a maintenance reserve and a management fee into every run by default; raise or lower those three sliders to match your actual market and a marginal deal will show itself before you sign anything. A property manager typically charges somewhere in the 8% to 10% of collected rent range, and a maintenance reserve of roughly 1% of the purchase price per year is a common starting assumption for a property in reasonable condition; older housing stock usually needs more.
Once you have a cash flow number, two follow-up questions usually come up: what will closing cost you up front, and what happens to the payment if you refinance later. Run the numbers on the upfront closing cost breakdown before you make an offer, and bookmark the refinance break-even tool for the day rates drop. If the property carries a mortgage with less than 20% down, the full PITI payment estimator shows the escrow piece this page treats as flat inputs.
Often 5 to 10% depending on market and risk. Higher cap rates usually mean higher risk or lower-growth areas.
Annual cash flow divided by the cash you invested (down payment and closing).
Ignoring them overstates returns; they're real, recurring costs of owning a rental.
Cash flow plus annual principal paydown, over your invested cash.
No - it's a planning estimate.