Buying a rental property is a business, not a hobby, and the only way to know if a deal works is the math. The Rental Property ROI Calculator estimates your annual return on investment from rent, expenses, financing, and appreciation — so you can compare a potential property against stocks or other investments.
It is built for small landlords and first-time investors who want a clear, conservative number before committing hundreds of thousands of dollars.
Real-estate seminars sell hype; this calculator sells clarity. Run it on every deal before you wire a deposit.
What This Calculator Does
It models a rental's annual cash flow and overall return. You enter the purchase price, down payment, loan terms, expected monthly rent, and operating expenses (taxes, insurance, maintenance, vacancy, management). It returns net operating income, cash-on-cash return, and cap rate.
Those three numbers together tell you whether the property throws off cash, appreciates on paper, or both — and how much your financing choice changes the answer.
The Formulas
NOI = Rent×12 − Operating Expenses Cap Rate = NOI ÷ Property Price Cash-on-Cash = Annual Cash Flow ÷ Cash Invested
Cash invested is your down payment plus closing costs and repairs. The calculator separates leverage (cash-on-cash) from unlevered return (cap rate) so you see the effect of financing.
Worked Example
| Item | Value |
|---|---|
| Price / down | $250,000 / $50,000 |
| Monthly rent | $1,800 |
| Operating costs/yr | $6,000 |
| NOI | $15,600 |
| Cap rate | 6.2% |
| Cash-on-cash | ~9% |
With 20% down, leverage lifts the cash-on-cash return above the cap rate — but only while the property stays occupied and rates stay manageable.
Why Cap Rate and Cash-on-Cash Differ
Cap rate ignores financing and reflects the asset itself; cash-on-cash reflects your actual out-of-pocket return with a mortgage. A good property can have a modest cap rate but a strong cash-on-cash return thanks to leverage — and vice versa.
The Vacancy and Repair Buffer
Every model should assume vacancies (typically 5–8% of rent) and maintenance (roughly 1% of price per year). Skipping these makes ROI look better than reality and is the most common beginner mistake — the difference between a 9% and a 4% return.
A Real Investor Scenario
An investor finds a $250,000 duplex renting for $1,800. Optimistic math (no vacancy, no repairs) shows a 12% cash-on-cash. The calculator, with 7% vacancy and 1% maintenance, drops it to ~9%. Still solid — but the honest number prevents over-leveraging and keeps a cushion for the inevitable roof bill.
Who Should Use This
First-time landlords, seasoned investors screening new markets, and anyone comparing a rental purchase to index-fund investing. It pairs naturally with our Rent Affordability Calculator to gauge tenant demand.
How to Use the Result
Compare the cash-on-cash return to your alternative investments and risk tolerance. Then estimate the tenant's perspective on rent with our Rent Affordability Calculator to gauge whether the market supports your rent.
Risks the Math Cannot Remove
- Bad tenants. Damage and non-payment dwarf a point of cap rate.
- Interest rate risk. Adjustable loans can erase cash flow.
- Local regulation. Rent-control and eviction rules vary by state — check our state guides.
Methodology, Assumptions & Data Sources
The return model uses standard landlord accounting. Net operating income (NOI) is gross rent times twelve minus operating expenses; cap rate is NOI divided by price; cash-on-cash is annual cash flow divided by your actual cash in (down payment, closing, initial repairs). We separate the unlevered cap rate from the levered cash-on-cash precisely so you can see how much financing changes the answer.
Rent levels come from local market data; expense ratios (vacancy, maintenance, management) are planning assumptions you should tighten with the actual property's history. The tool is conservative by design — better to be pleasantly surprised than wrongly confident.
When the Return Is a Mirage
Two inputs wreck ROI models: zero vacancy and zero maintenance. A unit that is 'always occupied' is fiction; assume 5–8% vacancy. A building with no repairs is fiction; assume roughly 1% of price per year. Skip those and the 'return' can halve in year one of a real problem.
Leverage cuts both ways. A low down payment lifts cash-on-cash but raises monthly risk if rates rise or the tenant leaves. Model a vacancy scenario explicitly before committing — the calculator's inputs make that easy.
Screening Deals Like a Pro
Run every candidate through the same conservative assumptions so you compare like for like. If a listing's rent seems too good, question it; if expenses seem too low, raise them. The cap rate tells you about the asset, the cash-on-cash about your specific financing — weigh both.
Then sanity-check tenant demand with our Rent Affordability Calculator: if local incomes cannot support your rent, your vacancy assumption will be optimistic.
Key Terms to Know
- NOI. Net operating income: rent minus operating costs, before debt.
- Cap rate. NOI ÷ price; return ignoring financing.
- Cash-on-cash. Annual cash flow ÷ cash invested; return with leverage.
- Vacancy rate. Assumed empty time; typically 5–8%.
- Maintenance. Usually modeled at ~1% of price per year.
Frequently Asked Questions
Many investors target a cash-on-cash return of 6–10% and a cap rate of 4–8%, but 'good' depends on location, financing, and risk. Use the calculator with conservative vacancy and repair assumptions.
Cap rate is return on the full property price (no loan); cash-on-cash is return on your actual cash invested (with a mortgage). Leverage usually makes cash-on-cash higher.
Yes — assume 5–8% of rent for vacancies and about 1% of price per year for maintenance, or the ROI will be unrealistically high.
It focuses on current income (NOI, cap rate, cash-on-cash). Appreciation is uncertain and is best modeled separately as a sensitivity case.