Rental Property Cash-Flow Calculator
About this calculator
Free, instant, and backed by a CPA-led qualified intermediary — built for investors weighing a buy, a sale, or a 1031 exchange.
Free, instant, CPA-led QI
The tool is free, runs in your browser, and stores nothing you enter. Behind it is Universal Pacific, a qualified intermediary led by a CPA. When you sell a rental and reinvest, we hold your exchange funds, prepare the documents, and keep your 45- and 180-day deadlines on the calendar so nothing slips.
What the calculator tells you
Enter the rent, your costs, and the mortgage and get the monthly and annual cash flow a rental generates, plus the cash-on-cash return on the money you put in. You also see the full income-and-expense breakdown and a read on whether the property runs at a profit or a loss.
How rental cash flow works
A few inputs, one subtraction, and a clear view of what the property pays you and what it returns on your cash.
Effective rent and vacancy
Start with the gross rent, then trim it for the weeks a unit sits empty between tenants. If you charge $2,400 and use a 5% vacancy allowance, effective rent is $2,280. That allowance is a planning figure, not a guarantee, and it should reflect your local market and how long your turnovers actually run.
Effective rent, not gross rent, is the honest starting line for cash flow. Skipping vacancy makes every other number look better than it is.
Operating expense categories
Operating expenses are the recurring costs of running the property: property taxes, landlord insurance, maintenance and a repair reserve, management fees, HOA dues, and any utilities you pay rather than the tenant. Management is usually quoted as a percent of collected rent, often 8% to 10%, so this calculator applies it to effective rent.
Capital expenses such as a new roof or HVAC are not in here. Budget for them separately, since they hit hard and irregularly.
Why the mortgage sits apart from cap rate
Cash flow subtracts the mortgage; the cap rate does not. That is the key split. Cap rate measures the property regardless of how it is financed, so two buyers see the same rate on the same building. Cash flow measures your result, which depends entirely on your down payment, rate, and term.
A property with a healthy cap rate can still run negative each month if the loan is large or expensive. Both numbers matter; they answer different questions.
Cash-on-cash vs. cap rate
Cash-on-cash return divides annual cash flow, after the mortgage, by the cash you actually invested: down payment, closing costs, and rehab. It tells you what your money earns this year. Cap rate divides net operating income by the full price and ignores debt.
Use cap rate to compare properties on equal footing, and cash-on-cash to judge what a specific deal, with your financing, returns on the dollars you committed. For the bigger picture across a full hold, see the real estate ROI calculator.
How it works
Five steps from a rental's numbers to the cash flow and return it produces.
Enter the rent
Add the gross monthly rent and a vacancy allowance to get effective rent.
Add expenses
Use one operating-expense total, or itemize taxes, insurance, repairs, and more.
Add the mortgage
Enter principal and interest, plus the cash you invested in the deal.
Read the result
See monthly and annual cash flow and your cash-on-cash return.
Plan the tax
Selling to reinvest? A 1031 exchange can defer the tax. Talk to a QI.
Frequently asked questions
The questions investors ask most about rental cash flow.
What counts as good monthly cash flow on a rental?
There is no fixed dollar target, since a $200 monthly profit means very different things on a $40,000 investment versus a $150,000 one. That is why cash-on-cash return matters more than the raw dollar figure: it puts cash flow against the money you put in. Many investors look for a return that beats what the same cash would earn elsewhere at a comparable risk. Run your own numbers and compare them to other uses for that capital.
Should I include the mortgage in cash flow?
Yes. Cash flow is meant to show what the property puts in your pocket, so it subtracts the full principal-and-interest payment. This is the main difference between cash flow and the cap rate, which leaves financing out so properties can be compared regardless of how each buyer pays for them. If you want to compare two buildings on equal footing, use the cap rate; if you want to know what a deal returns on your cash, include the mortgage.
What vacancy rate should I use?
A 5% allowance is a common starting point, but the right figure depends on your market, the unit, and how long your turnovers take. A single-family home in a tight rental market might run lower; a unit in an area with frequent moves or seasonal demand might run higher. Look at how many weeks your units actually sit empty between tenants and translate that into a yearly percent rather than borrowing a national average.
Why is my cash flow positive but cash-on-cash return low?
Positive cash flow only means the property earns more than it costs to run and finance each month. Cash-on-cash return compares that yearly profit to the cash you invested, so a large down payment or heavy rehab can produce a thin return even with a comfortable monthly margin. If the return looks low, you are tying up a lot of capital for the income you get; a smaller down payment or a different property might use that cash more efficiently.
Does this calculator account for taxes and depreciation?
No. It shows pre-tax operating cash flow only. Real estate also offers depreciation and other deductions that can lower the income tax you owe, sometimes turning a modest pre-tax profit into a better after-tax result. Those effects depend on your basis, your income, and your overall return, so a CPA should run them on your specific situation rather than a general calculator.
Can I defer tax when I sell a rental that has gained value?
Often, yes. A 1031 exchange lets you sell an investment property and reinvest the proceeds into another, deferring capital gains tax and depreciation recapture if you follow the rules and timeline. You identify replacement property within 45 days and close within 180, and a qualified intermediary holds the funds in between. The 1031 exchange calculator estimates what you could defer, and our team can set up the exchange.
Selling a rental to buy another?
Run the cash flow, then keep more of your gain. A 1031 exchange can defer the tax when you sell one income property and reinvest in another. Universal Pacific sets up the exchange, holds the funds, and tracks every deadline with you.
Contact our team