Rental Property Calculator

Use this calculator to estimate the monthly cash flow of a rental property, along with its net operating income (NOI), cap rate, cash-on-cash return and debt service coverage ratio (DSCR). It is a first screen to decide whether a property deserves a closer look, not a final investment analysis.

Estimated monthly cash flow

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    This calculator gives simplified estimates for educational purposes only. Actual results depend on your market, financing, taxes, and how the property is managed. It is not financial or investment advice.

    How to use the rental property calculator

    • Purchase price, down payment, interest rate and term: these set the loan and the monthly mortgage payment (principal and interest). Investment property loans can be priced differently from loans for a home you live in, so use a rate quoted for this type of purchase.
    • Closing costs and initial repairs: the cash you need on top of the down payment before the property can be rented.
    • Monthly rent: base it on comparable rentals near the property. HUD’s Fair Market Rents, which estimate 40th-percentile gross rents for standard-quality units by metro area or county, can serve as a cross-check.
    • Vacancy: the share of the year you expect the unit to be empty.
    • Property tax and insurance: yearly amounts. Use the actual tax bill and an insurance quote when you have them.
    • Maintenance, CapEx reserve and property management: each as a percentage of collected rent. Maintenance covers routine repairs; the CapEx reserve sets money aside for large replacements such as a roof or water heater; management is the fee a property manager charges. Set management to 0 if you will manage the property yourself.
    • Other expenses: anything else you pay monthly, such as HOA dues or utilities the landlord covers.

    How to read the results

    • Monthly cash flow: collected rent minus operating expenses minus the mortgage payment. The box turns red when it is negative.
    • Net operating income (NOI): yearly collected rent minus operating expenses, before the mortgage.
    • Cap rate: NOI divided by the purchase price. It describes the property’s income independently of how you finance it.
    • Cash-on-cash return: yearly cash flow divided by the cash you put in (down payment plus closing costs and repairs).
    • DSCR: NOI divided by yearly mortgage payments. Below 1.00 means the property’s income does not cover the loan payments on its own.
    • Rent-to-price ratio: monthly rent as a percentage of the price. The “1% rule” is a rough screening shortcut, not a substitute for the full numbers above.

    Examples

    Both hypothetical scenarios use a $300,000 property, a 7% rate on a 30-year loan, $15,000 in closing costs and repairs, $2,700 monthly rent, 5% vacancy, $4,000 property tax, $1,500 insurance, 8% maintenance and a 5% CapEx reserve. They are illustrations, not market data.

    A: 20% down, professional management (8%)B: 25% down, self-managed
    Collected rent$2,565/mo$2,565/mo
    Operating expenses$997/mo$792/mo
    Mortgage payment (P&I)$1,597/mo$1,497/mo
    Monthly cash flow−$29$276
    NOI$18,816/yr$21,279/yr
    Cap rate6.27%7.09%
    Cash invested$75,000$90,000
    Cash-on-cash return−0.46%3.68%
    DSCR0.981.18

    Scenario A loses a little money every month even though the rent looks healthy: after vacancy, expenses and the loan payment, nothing is left. Scenario B turns positive because the owner borrows less and does the management work. That work has a cost in time, and the extra $15,000 of cash could have been used elsewhere, so a positive number is not automatically the better deal.

    Lenders also discount rent. For a purchase, Fannie Mae’s Selling Guide calculates net rental income as 75% of gross monthly rent before comparing it with the housing payment. If your plan only works at 100% occupancy and zero repairs, it is fragile.

    Limitations

    • It looks at one year of operation. It does not include rent growth, appreciation, loan paydown or selling costs.
    • It ignores income taxes. Rental income and deductible expenses, including mortgage interest, repairs, insurance, management fees and depreciation, are reported on Schedule E; residential rental buildings are depreciated over 27.5 years under the general system, as explained in IRS Publication 527. Ask a tax professional how this applies to you.
    • Percent-based maintenance and CapEx are averages. Older buildings can need far more in a single year.
    • It models long-term rentals. Short-term rentals have different costs and occupancy (see Rental Property vs Airbnb).
    • It is not financial or investment advice.

    Related guides

    Sources

    Last updated: October 5, 2026. By Ferran Pujol Acosta.

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