UtilibyWritten by the Utiliby editorial team · Last updated October 12, 2026 · Rules and formulas reviewed October 2026
What a rental property cash flow calculator tells you
A rental property cash flow calculator turns an advertisement into a set of numbers you can compare: how much money is left each month after every cost, how hard your cash works, and how safe the payment is. It matters because a property can look attractive by price or rent alone and still lose money once vacancy, repairs, insurance, tax and the mortgage are counted.
This free online tool calculates monthly cash flow, cash-on-cash return, cap rate, DSCR, gross rent multiplier, break-even occupancy and the 1%, 2% and 50% rules. It also projects rent, expenses, loan balance, equity, sale proceeds and IRR for up to 30 years and builds what-if tables for rate, rent, vacancy, down payment and price. For a quick gross and net yield check, use the Rental Yield Calculator. Everything runs in your browser.
How to use this rental calculator
- Enter the price and financing. Choose a mortgage and enter the down payment, rate and term, or choose all cash.
- Add closing costs and repairs. These count as cash invested.
- Enter income. Use realistic monthly rent, any extra income and a vacancy rate.
- Enter operating expenses. Use actual quotes for tax and insurance, and percentages for maintenance, capital expenses and management.
- Read the verdict and rule-of-thumb checks. Then open the what-if tab to stress-test rent, rate and vacancy.
- Open the projection. Pick a holding period to see equity, sale proceeds, IRR and the equity multiple.
The rental property formulas
| Measure | Formula |
|---|---|
| Effective income | Rent + other income − vacancy |
| NOI | Effective income − operating expenses |
| Cash flow | NOI − yearly loan payments |
| Cash invested | Down payment + closing costs + repairs |
| Cash-on-cash | Yearly cash flow ÷ cash invested |
| Cap rate | NOI ÷ purchase price |
| DSCR | NOI ÷ yearly loan payments |
| GRM | Price ÷ yearly rent |
| Break-even occupancy | (Operating costs + loan payments) ÷ potential income |
Worked example. A 250,000 property with 25% down, a 7% 30-year loan and rent of 2,200 a month has cash invested of about 75,000. After 6% vacancy, tax, insurance, maintenance, capex and management, NOI is about 15,800 a year. Loan payments are about 15,000, so cash flow is about 800 a year, a cash-on-cash return near 1%. The deal looks fine on rent-to-price but is thin once the mortgage is paid, which is why the full calculation matters.
The 1%, 2% and 50% rules
- 1% rule. Monthly rent should be about 1% of the price. Higher prices make this hard to meet, so treat it as a screen.
- 2% rule. Rent of 2% of the price is the rare high-yield benchmark.
- 50% rule. Operating costs, excluding the mortgage, average roughly half of income. If your inputs are far below 50% check that you included repairs, capex and vacancy.
These are quick filters. The final decision should rest on cash flow, cash-on-cash, DSCR and your own reserves.
Cash-on-cash return, cap rate and DSCR compared
Cap rate measures the property, ignoring how you pay for it. Cash-on-cash measures your cash, so it reflects the loan. DSCR measures safety, showing how well income covers the payment. A property can have a strong cap rate but weak cash-on-cash if the rate is high, or a good cash-on-cash and a thin DSCR if you borrowed heavily. Looking at all three gives a more complete picture.
The projection, IRR and equity multiple
The projection grows rent and expenses by the rates you enter, tracks the mortgage balance and property value, and assumes you sell at the end after selling costs. Equity is value minus loan. IRR is the annual return that equates your cash invested with the stream of yearly cash flows and the final sale. The equity multiple shows total cash back for each dollar invested. Because growth is constant, treat the result as a scenario, not a forecast.
Risks that spreadsheets often miss
- Vacancy longer than planned and bad debt.
- Large repairs: roofs, boilers, plumbing, sewers.
- Rising insurance and tax bills after a purchase reassessment.
- Rent controls or notice rules that limit increases.
- Variable or short-term loans that reset at higher rates.
- Concentrating all your cash in one property.
Tips for a more reliable analysis
- Use quotes for insurance and an actual tax estimate for your purchase price.
- Check rent against active and recently let comparable listings.
- Always include repairs, capital expenses and vacancy.
- Test a higher rate and 10% lower rent in the what-if tables.
- Keep six months of reserves per property.
- Compare against a lower-risk use of the same cash.
Common mistakes
- Leaving out vacancy, repairs and management because you plan to self-manage.
- Using the seller's tax bill when a sale will trigger reassessment.
- Confusing gross yield with net yield or cap rate.
- Ignoring closing costs and initial repairs in cash invested.
- Assuming rents and values only go up.
A full example: reading the results together
Take the default property: 250,000 price, 25% down, a 7% 30-year loan and 2,200 rent. The cap rate of about 6.3% looks respectable, and the gross rent multiplier of 9.5 is not unusual. But the DSCR is only about 1.05 and the cash-on-cash return about 1%, which means the loan payment takes nearly all of the net operating income. The deal is not a failure, since the first-year total return including loan paydown and appreciation is far higher than cash flow alone, but it is fragile: a single month of vacancy or a 1 point rate rise turns cash flow negative, as the what-if table shows.
Now change one thing at a time. Raise the down payment to 35% and the cash flow improves but cash-on-cash may still be weak because you invested more. Lower the price by 10% and both measures improve a lot. Raise rent by 5% and cash flow moves more than it appears, because expenses that are percentages of rent rise less than rent. This is the real value of a calculator: you can see which lever matters most before you negotiate or choose a lender.
Mortgage, cash and DSCR loans compared
Conventional investor mortgages usually need a larger down payment than a home you live in and are underwritten on your income. DSCR loans look mainly at the property's income, which is why DSCR appears in the results; many lenders want 1.0 to 1.25 or more. Cash buyers avoid interest but tie up capital. Switch the financing selector to compare. A leveraged purchase raises cash-on-cash return when the property yield is higher than the loan rate, and lowers it when the loan rate is higher than the yield, so rising rates make leverage less attractive.
Choosing realistic inputs for your market
Rent: look at recently let comparable properties, not asking rents, and note how long they stayed on the market. Vacancy: ask local property managers for typical turnover time. Tax: use the rate that will apply after purchase, since some areas reassess at sale. Insurance: get a quote, especially in areas with wind, flood or wildfire exposure, where premiums have risen sharply. Maintenance and capital expenses: older roofs, boilers, plumbing and appliances justify higher percentages. Management: even if you manage yourself, include a fee so the deal still works if you stop.
Privacy
The calculator runs in your browser. The figures you enter are not sent to a server and are not stored. Reloading the page returns the example property. Downloaded files are created on your device.
Related free tools
Use these free online tools together with this one:
- Plan a buy, rehab, rent and refinance deal with the BRRRR calculator.
- Work out rent for a part month with the prorated rent calculator.
- Estimate what you keep after a sale with the home sale net proceeds calculator.
- Compare contractors and suppliers with the vendor comparison tool.
- Estimate what a home's electricity could cost with the electricity cost calculator.
- Add rent due dates to your calendar with the ICS file generator.
Frequently asked questions
How do you calculate rental property cash flow?
Cash flow = rent and other income − vacancy − operating expenses − loan payments. Operating expenses include property tax, insurance, maintenance, capital expenses, management, HOA and utilities. This calculator does each step and shows a monthly and yearly figure.
What is NOI in real estate?
Net operating income is income after vacancy and operating expenses but before loan payments and income tax. It is used to compute cap rate and DSCR.
What is cash-on-cash return?
It is yearly pre-tax cash flow divided by the cash you invested (down payment, closing costs and repairs). A 10,000 cash flow on 100,000 invested is a 10% cash-on-cash return.
What is a good cash-on-cash return for a rental?
Many investors look for 8% to 12%, but the right number depends on your market, risk and alternatives. Use the target field to see the highest price that still reaches your goal.
What is a cap rate and how is it different from cash-on-cash?
Cap rate is NOI divided by the purchase price and ignores financing. Cash-on-cash uses cash flow after the loan and your invested cash, so it changes with your down payment and rate.
What is DSCR?
Debt service coverage ratio is NOI divided by yearly loan payments. A DSCR of 1.0 means income exactly covers the loan. Lenders for investment loans often want 1.2 or more.
What is the 1% rule?
The 1% rule is a screen that monthly rent should be at least 1% of the purchase price. A 250,000 property should rent for about 2,500. It is a quick filter, not a guarantee of cash flow.
What is the 2% rule?
The 2% rule asks for monthly rent of 2% of price. It is rare today and is mostly met by low-priced properties in some markets, which may come with higher risk.
What is the 50% rule?
The 50% rule estimates that operating expenses, excluding the mortgage, take about half of rental income over time. This calculator compares your actual expense ratio to it.
What vacancy rate should I use?
Use the typical vacancy in your area, often 5% to 10%. Never use 0% unless the property is guaranteed to be let continuously, because turnover and make-ready time are real costs.
How much should I budget for maintenance and capital expenses?
A common rule is 5% to 10% of rent for repairs and another 5% to 10% for big items such as roofs, boilers and appliances. Older properties need more.
What is break-even occupancy?
It is the share of the year the property must be let to cover operating costs and the loan. A lower number means a bigger safety cushion.
What is gross rent multiplier?
GRM is the purchase price divided by yearly rent. Lower numbers mean more rent for the price. It is useful for quick comparison but ignores expenses.
What is IRR and the equity multiple?
IRR is the yearly return that makes the cash invested equal to all later cash flows plus sale proceeds. The equity multiple is total cash returned divided by cash invested. The projection tab calculates both.
Does the calculator include taxes and depreciation?
It shows pre-tax figures. Depreciation and income tax depend on your situation and country, so ask a tax professional.
Can I compare a mortgage with an all-cash purchase?
Yes. Switch financing between mortgage and all cash and compare cash-on-cash, cash flow and IRR. Leverage can raise returns but also raises risk.
How is this different from the Rental Yield Calculator?
The Rental Yield Calculator gives gross and net yield quickly. This tool adds the loan, cash-on-cash return, DSCR, the 1%, 2% and 50% rules, a projection and what-if tables.
Is my data private, and can I print or export?
Yes. Everything runs in your browser and nothing is uploaded. You can print only the report, download a CSV or copy a summary.
Sources and further reading
- Standard real estate investment analysis texts on net operating income, cap rate, cash-on-cash return and debt service coverage ratio.
- Consumer Financial Protection Bureau: explanations of mortgage payments, closing costs and escrow.
- Common investor rules of thumb (1% rule, 2% rule, 50% rule) as widely described in investing education; they are screens, not guarantees.
- Investor loan lender published guidelines for DSCR requirements (terms vary by lender; confirm current quotes).
Sources were consulted in October 2026. Standards and rules can change, so always check the official page for your situation.