Rental Property Calculator Online
Analyze a rental property's cash flow, cap rate, and cash-on-cash return right in your browser. Estimates only — not financial advice.
The Rental Property Calculator runs entirely in your browser. The purchase price, rent, and expense figures you enter never leave your device and nothing is uploaded to ArrayKit. Results are estimates only, not financial advice.
Open the ROI Calculator
About Rental Property Calculator
The Rental Property Calculator analyzes a potential rental purchase using purchase price, down payment, mortgage terms, rent, and operating expenses to produce four key numbers: net operating income (NOI), cap rate, monthly cash flow, and cash-on-cash return. Toggle on the advanced fields to factor in a vacancy rate, annual property tax, and insurance for a more realistic picture of effective rent and true operating costs. It applies the standard investor formulas — NOI as effective annual rent minus operating expenses, cap rate as NOI divided by purchase price, and cash-on-cash return as annual cash flow divided by your down payment — so you can quickly screen a single-family rental, a duplex, or a small multifamily deal before running deeper due diligence. Everything runs locally in your browser and your property figures are never uploaded. Estimates only — not financial advice.
Features
- Computes net operating income (NOI) from effective rent and operating expenses
- Computes cap rate as NOI divided by purchase price
- Computes monthly and annual cash flow after the mortgage payment
- Computes cash-on-cash return using your down payment as cash invested
- Optional vacancy rate lowers effective rent to match real occupancy
- Optional annual property tax and insurance fields for accurate expenses
- Handles an all-cash purchase (down payment equal to price) with zero mortgage payment
- Runs entirely in your browser with no property numbers uploaded
How to use the Rental Property Calculator
- Enter the purchase price, down payment, interest rate, and loan term
- Enter expected monthly rent and monthly operating expenses
- Optionally toggle advanced settings for vacancy rate, property tax, and insurance
- Read monthly cash flow, cap rate, cash-on-cash return, and NOI below the inputs
- Copy the summary to paste into your notes or a deal spreadsheet
Example
Input
$300k, 20% down, $2,200 rent
Output
Cash flow: $250/mo
Cap rate: 5.8%
Common errors & troubleshooting
- Result shows 'Down payment cannot exceed the purchase price.' — Enter a down payment that is a portion of the purchase price, not equal to or greater than it — unless you are modeling a fully paid-off, all-cash purchase, in which case set it equal to the price.
- Cap rate looks too high compared to cash-on-cash return. — Cap rate ignores financing and is based on NOI over the full purchase price, while cash-on-cash return only divides by your down payment — a smaller down payment on the same property will always produce a larger (or smaller, if cash flow is negative) cash-on-cash figure than the cap rate.
- Monthly cash flow is negative even though rent covers the mortgage. — Cash flow subtracts the full mortgage payment plus operating expenses, taxes, insurance, and any vacancy loss from rent — check the advanced fields to make sure taxes and insurance are not being double-counted inside monthly expenses.
- Entered the interest rate as 0.065 instead of 6.5. — Enter the interest rate as a whole percent (6.5 for 6.5%), not a decimal fraction — 0.065 will be treated as 0.065% and produce an unrealistically low mortgage payment.
Frequently asked questions
- What does the Rental Property Calculator compute?
- It computes net operating income (NOI), cap rate, monthly cash flow, and cash-on-cash return for a rental property from the purchase price, financing terms, rent, and operating expenses you enter.
- How does the Rental Property Calculator figure NOI?
- NOI equals effective annual rent (monthly rent adjusted for vacancy, times 12) minus annual operating expenses, which include your monthly expenses times 12 plus any property tax and insurance you enter. NOI excludes the mortgage payment.
- How is cap rate different from cash-on-cash return in this calculator?
- Cap rate divides NOI by the full purchase price and ignores financing, so it lets you compare properties as if bought in cash. Cash-on-cash return divides annual cash flow (after the mortgage payment) by your actual down payment, reflecting the return on the cash you put in.
- Does the vacancy rate change the cap rate shown by the Rental Property Calculator?
- Yes. When you turn on the advanced settings, the vacancy rate reduces effective monthly rent before NOI is calculated, which lowers both NOI and cap rate to reflect realistic occupancy rather than 100% occupancy.
- Can the Rental Property Calculator model an all-cash purchase?
- Yes. Set the down payment equal to the purchase price and the loan amount and mortgage payment both become zero, so monthly cash flow equals NOI divided by twelve with no debt service.
- Is the Rental Property Calculator financial advice?
- No. It is a quick estimator based on the numbers you type. Estimates only — not financial advice. Verify any purchase decision with a qualified professional, actual lender quotes, and full local expense figures including maintenance and repairs.
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