How it works
A rental analysis begins with the income the property can collect, then separates operating expenses from financing. Monthly cash flow is the amount left after both costs and the entered replacement reserve.
The formula
Keep currency, units and time periods consistent. Percentage inputs use percentage points (enter 5 for 5%). Results are rounded only for display; tiny nonzero values may use scientific notation. Undefined ratios are shown as unavailable.
$3,100 monthly income, 5% vacancy and $900 operating expenses produce $24,540 annual NOI. After $1,500 monthly debt service, cash flow is $545/month ($6,540/year). A $300,000 price gives 8.18% cap rate; $90,000 invested gives 7.27% cash-on-cash.
Calculation method
Enter combined rent for all units, or use the per-unit rent list to sum different rents. Itemized expenses replace the operating-expense total when any item is entered. An optional loan amount replaces the payment with an amortized payment.
Interpretation
Cap rate describes the property before financing. Cash-on-cash describes income relative to your actual cash at risk. Enter only cash-paid acquisition costs in the cash basis; financed costs must not be counted twice.
Limitations
All rents, values, vacancy, expenses and financing terms are your assumptions. Figures exclude income tax and appreciation. Inputs stay in your browser. These calculations do not predict loan approval or investment outcomes.
Method and reference sources
Method and content checked 2026-09-20. These sources provide background, not endorsement or professional certification. The formula and limitations above define this calculator.
- CFPB — How lenders calculate mortgage paymentsLoan principal-and-interest context; property operating expenses and underwriting assumptions are separate.
Frequently asked questions
Is positive NOI the same as positive cash flow?
No. NOI excludes financing. Mortgage debt service and other cash items can turn positive operating income into negative cash flow. Review both results.
What is a worked example for Rental Property?
$3,100 monthly income, 5% vacancy and $900 operating expenses produce $24,540 annual NOI. After $1,500 monthly debt service, cash flow is $545/month ($6,540/year). A $300,000 price gives 8.18% cap rate; $90,000 invested gives 7.27% cash-on-cash.