Rental Property Calculator
Analyze a rental deal end to end: monthly cash flow, net operating income, cap rate, and cash-on-cash return from the purchase price, financing, rent, expenses, and vacancy. Screen properties fast before you make an offer.
How to Use
- Enter the purchase price and your down payment.
- Enter the mortgage rate and term to set the loan payment.
- Enter the expected monthly rent and your monthly operating expenses (taxes, insurance, maintenance, management).
- Enter a vacancy percentage to discount rent for empty months.
- Read the results: effective rent, NOI, monthly and annual cash flow, cap rate, and cash-on-cash return.
Show Work
Metrics
About the Rental Property Calculator
The Rental Property Calculator is a free tool for personal-finance and money decisions. It runs right in your web browser, so there is nothing to download. Analyze a rental deal end to end: monthly cash flow, net operating income, cap rate, and cash-on-cash return from the purchase price, financing, rent, expenses, and vacancy. Screen properties fast before you make an offer.
How it works
Type your numbers into the boxes. The answer shows up right away — you do not have to press a button. If you change a number, the answer changes too. So you can try different numbers and watch what happens, or check an answer you worked out yourself. Just make sure each box has the right kind of number in it.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
What is net operating income (NOI)?
NOI is the annual income a property produces after operating expenses but before mortgage payments and income taxes. Here it is the effective rent (rent adjusted for vacancy) minus operating expenses, annualized. It measures the property's earning power independent of how it is financed.
What is a cap rate and what is good?
The capitalization rate is NOI divided by the purchase price, expressed as a percentage. It estimates the unleveraged annual return. What counts as "good" depends heavily on the market — strong, low-risk metros may trade at 4–5% caps while higher-risk areas demand 8%+. Compare against similar local sales rather than a fixed target.
How does cap rate differ from cash-on-cash return?
Cap rate ignores financing and measures return on the full purchase price. Cash-on-cash return divides your annual pre-tax cash flow (after the mortgage) by the actual cash you invested (your down payment and costs). Leverage can push cash-on-cash above the cap rate when the loan rate is below the cap rate.
Why include a vacancy allowance?
No rental stays occupied 100% of the time. A vacancy percentage (often 5–10%) discounts your gross rent to reflect turnover, downtime between tenants, and the occasional non-payment, giving a more realistic effective rent and cash flow.
Does this account for all the costs of owning a rental?
It covers the mortgage, operating expenses you enter, and vacancy, but you should make sure your expense figure includes property tax, insurance, maintenance reserves, capital expenditures, and management. It does not model appreciation, tax depreciation, or selling costs, so treat the output as an estimate for screening, not investment advice.
How do I use the Rental Property Calculator?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Is it free? Does it work without internet?
Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.
Where does my data go?
Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.
Common Use Cases
Screening a listing before offering
Plug in the asking price and market rent to see if the deal cash-flows before you spend time on due diligence.
Comparing two properties
Run a single-family home against a duplex to see which delivers a better cap rate and cash-on-cash return.
Testing your down payment
Adjust the down payment to see how leverage changes monthly cash flow and cash-on-cash return.
Stress-testing vacancy and expenses
Raise the vacancy rate or expenses to check whether the property still cash-flows in a tougher year.
Setting a target rent
Work backward from a desired cash flow to find the rent the property needs to command.
Last updated: