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How to Calculate Rental Property ROI (Cap Rate, Cash-on-Cash, and More)
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By Derek Giordano, BA Business Marketing · January 2026 · Reviewed for accuracy
Real estate investing has more metrics than almost any other asset class. Agents and sellers throw around cap rates, GRMs, and cash-on-cash figures — often selectively to make a property look attractive. Understanding what each metric actually measures (and what it ignores) is essential before writing any checks.
Cap Rate: The Property Metric
Cap Rate = Net Operating Income ÷ Purchase Price
NOI = Annual Gross Rent − Vacancy − Operating Expenses (taxes, insurance, maintenance, management). Crucially, NOI does not include mortgage payments — cap rate measures the property's return independent of how it's financed.
Cap rate is useful for comparing properties regardless of how you plan to finance them, and for quickly screening deals. A 7% cap rate property is more efficient at generating income from its purchase price than a 5% cap rate property.
What's a good cap rate? It depends heavily on market. In NYC or San Francisco, 3–4% cap rates are common because buyers are paying for appreciation, not cash flow. In the Midwest and South, 7–9% is achievable. Anything above 10% warrants investigation — it may indicate higher risk, needed repairs, or a difficult tenant base.
Cash-on-Cash Return: The Investor Metric
Cash-on-Cash = Annual Pre-Tax Cash Flow ÷ Total Cash Invested
Annual Cash Flow = NOI − Annual Mortgage Payments. Total Cash Invested = Down payment + closing costs + initial repairs.
This is the most practical metric for leveraged investors because it shows your actual cash return on the money you put in. A 10% CoC return means you're getting $10,000 back annually on a $100,000 cash investment — before any appreciation.
A property with a 5% cap rate can produce a 12% cash-on-cash return if financed at a low enough rate. Conversely, a 7% cap rate property financed at 7% might produce near-zero cash flow.
The Hidden Costs That Kill Returns
Most beginner investors run numbers with only mortgage + property tax. The real cost structure includes:
- Vacancy: Budget 5–10% of gross rents. Even great landlords have turnover gaps.
- Maintenance: Rule of thumb: 1–2% of property value per year. A $300,000 house = $3,000–6,000 in maintenance annually.
- CapEx reserves: Roof ($10,000–20,000 every 20–25 years), HVAC ($5,000–10,000 every 15 years), water heater ($1,500 every 10 years).
- Property management: If you don't self-manage, budget 8–12% of gross rents.
Analyze any property instantly with the Rental Property Calculator.
Frequently Asked Questions
What is a good cap rate for a rental property?
Cap rates vary by market and property type. In general, 5-8% is considered solid for residential rentals. Class A properties in prime locations often have lower cap rates (3-5%) but more appreciation potential, while Class C properties in secondary markets may offer 8-12% cap rates but higher vacancy and maintenance risk. Compare cap rates within the same market and property class, not across different regions.
What is the difference between cap rate, cash-on-cash return, and total ROI?
Cap rate measures property income relative to purchase price (ignoring financing). Cash-on-cash return measures annual cash flow relative to the cash you actually invested (including leverage effects). Total ROI includes appreciation, principal paydown, and tax benefits on top of cash flow. A property might have a 6% cap rate, 10% cash-on-cash return, and 15-20% total ROI once all factors are included.
How do I estimate rental income for a property I am considering buying?
Check comparable rents on Zillow, Rentometer, or Craigslist for similar properties within a half-mile radius. Adjust for condition, amenities, and unit size. Then apply a vacancy factor of 5-8% for stable markets or 8-12% for less predictable areas. The resulting net effective rent is your realistic income estimate. Never use the listing agent's projected rent without independent verification.
What expenses do new landlords most commonly underestimate?
The top underestimated expenses are: vacancy loss (5-10% of gross rent), maintenance and repairs (8-12% of rent for older properties), capital expenditure reserves for major systems (roof, HVAC, plumbing), property management fees (8-10% if not self-managing), insurance increases, and property tax reassessment after purchase. Budget conservatively using the
Property Tax Calculator for tax estimates.
Should I use the 1% rule when evaluating rental properties?
The 1% rule (monthly rent should be at least 1% of the purchase price) is a quick screening tool, not a definitive analysis. In high-cost markets, virtually no property meets this threshold, yet many still generate positive returns through appreciation and tax benefits. In lower-cost markets, properties exceeding 1% may carry higher risk. Use it as a first filter, then run a full cash flow analysis for any property that interests you.
Ready to run your own numbers? Use the free Rental Property Calculator — no signup required.