A rental property calculator estimates cash flow and returns after financing, vacancy, operating expenses, reserves, and exit assumptions—not just rent minus the mortgage.
Published by DealCooker. Product owner: Dillon Cook, Real estate agent and DealCooker creator.Last substantively updated .
Rental cash flow: what to check before you calculate
Rent minus the mortgage is only a starting point. A rental analysis also needs vacancy, taxes, insurance, operating costs and reserves. Gather property-specific evidence before treating a positive result as spendable income.
Rent and vacancy. Check leases, comparable rents and local vacancy conditions. Use your own supported assumptions, not a promise that the property will stay full.
Taxes and insurance. Check the tax estimate for the proposed purchase and obtain a property-specific insurance quote. In DealCooker, enter these separately from the loan terms. Do not count them again just because a lender includes them in an escrow payment.
Running costs and reserves. Include owner-paid utilities, HOA fees, management, maintenance and capital reserves where applicable. A reserve is a planning allowance; actual repairs and replacements can arrive unevenly.
Cash needed to start. Review the down payment, acquisition costs and rehab budget. Monthly cash flow does not show how much cash you need before the property starts operating.
Read the result in the right order
First, inspect modeled monthly cash flow after expenses, reserves and debt service. Next, compare cash-on-cash return with the cash invested; it is not the same as cap rate. Finally, review the full hold-period projection and test a lower-rent or higher-cost scenario before relying on the original result.
DealCooker's modeled NOI can include reserves and strategy-dependent fixed costs, so it may differ from a lender's NOI. Read the methodology for the calculator's definitions. The long-term rental placement-fee input is informational and excluded from returns; budget actual leasing costs separately.
These are pre-tax estimates, not investment advice or a forecast. Verify property facts and lender terms independently. For general context, see the CFPB's PITI explanation and IRS residential rental-property guidance. Tax-accounting rules are not the calculator's cash-flow model.
DealCooker can test a lower purchase price and, when applicable, a larger down payment against the active strategy’s workout logic. It does not optimize interest rates, points, loan products, or every financing term.
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Calculation methodology
How DealCooker models this strategy
DealCooker calculates effective income after vacancy, subtracts modeled operating costs and reserves to estimate NOI, subtracts debt service for cash flow, and builds a dated cash-flow timeline for total ROI and annualized IRR.
Purchase and closing costs, loan terms, rent, vacancy, management, maintenance, capital reserves, taxes, insurance, cash flow, sale assumptions, and return metrics should be connected in one model.
How is rental cash flow calculated?
DealCooker starts with rent and other income, subtracts vacancy and modeled expenses, then subtracts debt service. The result is a pre-tax estimate, not a guarantee.
Is cap rate the same as cash-on-cash return?
No. DealCooker models cap rate from annual NOI relative to acquisition basis, while cash-on-cash return compares annual pre-tax cash flow with cash invested.
Does DealCooker calculate taxes or give investment advice?
No. It is an educational screening tool. Verify rents, expenses, financing, zoning, insurance, taxes, and legal requirements with qualified professionals.
Primary references
Sources behind the context
DealCooker’s formulas come from its tested calculation engine. These external references support definitions, diligence reminders, or operating context—not the worked-example assumptions. Sources checked 2026-07-24.
