US Real Estate

Cap Rate Explained

The capitalization rate formula, how to calculate NOI consistently, how to compare properties, and where the metric can mislead.

Cap rate formulaNOI explainedRisk interpretationCap rate vs ROI

What is cap rate?

The capitalization rate — cap rate — is the most widely used metric for evaluating income-producing real estate. It measures the annual return a property generates relative to its value, assuming an all-cash purchase. Cap rate strips out financing so you can compare properties on the same footing regardless of how they're funded.

The formula is straightforward: Cap Rate = Net Operating Income ÷ Property Value. A property generating $24,000 of NOI purchased for $400,000 has a 6% cap rate. The inverse is also true — if you know a market trades at 6% cap rates, a property with $24,000 NOI should be worth roughly $400,000.

The cap rate formula

Cap rate — step by step
Gross rental income (annual)$36,000
Vacancy allowance (5%)−$1,800
Effective gross income$34,200
Operating expenses (taxes, insurance, mgmt, repairs)−$10,200
Net Operating Income (NOI)$24,000
Purchase price$400,000
Cap rate (NOI ÷ price)6.0%

What goes into NOI — and what doesn't

Getting NOI right is where most beginner investors make mistakes. NOI is income after operating expenses but before mortgage payments, depreciation and income taxes. It is a property-level metric, not an investor-level metric.

Included in NOI

  • Gross rent (all units)
  • Less: vacancy & credit loss
  • Less: property taxes
  • Less: insurance
  • Less: property management fees
  • Less: maintenance & repairs
  • Less: utilities (landlord-paid)
  • Less: HOA / common area costs

Not included in NOI

  • Mortgage principal & interest
  • Depreciation
  • Income tax
  • Capital expenditures (roof, HVAC)
  • Loan origination fees
  • Personal expenses
  • Closing costs at purchase
  • Investor's own management time

Capital expenditures (CapEx) are often omitted from NOI because they are not recurring operating expenses. That does not make them economically irrelevant. Model a property-specific replacement reserve and acquisition costs separately so the cap rate does not hide roofs, HVAC systems, or other irregular capital needs.

How to interpret a cap rate

There is no durable national table of “good” cap rates. The figure varies with property type, condition, leases, expenses, location, growth expectations, liquidity, and the date of valuation. A higher cap rate can indicate more current income, more risk, or both.

CompareKeep constantWhat to investigate
Two propertiesValuation date and NOI methodCondition, tenants, leases and deferred work
Two neighborhoodsProperty type and qualityVacancy, demand, regulation and liquidity
Purchase vs current valueThe same normalized NOIWhether the denominator answers your question
Cap rate vs financingUnlevered property cash flowDebt service and cash invested separately

For a live benchmark, use recent comparable transactions for the same asset type and normalize their NOI on the same basis. Listing cap rates are not substitutes for verified income, expenses, and sale prices.

Cap rate vs cash-on-cash return

Cap rate and cash-on-cash (CoC) return are related but measure different things. Cap rate is financing-agnostic — it tells you about the property. Cash-on-cash measures your actual cash return on the equity you deployed, including the effect of leverage.

Illustration — cap rate vs cash-on-cash with leverage
Purchase price$400,000
NOI$24,000
Cap rate (NOI ÷ price)6.0%
Down payment (25%)$100,000
Other acquisition cash (assumed)$10,000
Annual mortgage payments−$17,100
Annual cash flow after debt service$6,900
Cash-on-cash return ($6,900 ÷ $110,000)6.3%

In this illustration, leverage produces a cash-on-cash return close to the cap rate. Leverage works both ways: if NOI falls, cash flow shrinks while scheduled debt service remains. The result changes with the actual interest rate, loan terms, closing costs, and reserves.

The cap rate and interest rate relationship

Interest rates can affect required returns, financing costs, and property values, but cap rates do not move in a fixed spread to the 10-year Treasury. Property income growth, risk, transaction liquidity, leverage availability, and local supply can change the relationship.

Scenario inputPotential effectWhat to test
Higher borrowing costLower leveraged cash flowDebt-service coverage and cash-on-cash return
Higher required returnDownward pressure on valueValue at several exit cap rates
Stronger expected NOI growthMay support a lower going-in capRent, vacancy and expense assumptions
Key point

Cap rate is a valuation and comparison tool — not a measure of your actual return. A 7% cap rate in Indianapolis is not the same investment as a 4% cap rate in San Francisco: risk profile, liquidity, appreciation potential and tenant quality differ significantly. Use cap rate to screen and compare deals, then model the full return including leverage, CapEx reserves, tax benefits and exit assumptions before committing capital.

Frequently asked questions

Is a higher cap rate always better?
Not necessarily. A higher cap rate may reflect stronger current income, higher vacancy or repair risk, weaker liquidity, or different growth expectations. Compare verified NOI and investigate why the market prices the property at that yield.
Does cap rate include mortgage payments?
No. Cap rate is calculated from Net Operating Income before debt service. It deliberately excludes financing so you can compare properties on an unlevered basis. Your actual cash return after mortgage payments is measured by cash-on-cash return, which will be higher or lower than the cap rate depending on your leverage and interest rate.
What is a good cap rate for a rental property?
There is no universal threshold. Compare recent sales of similar properties using consistently normalized NOI, then test vacancy, repairs, financing, capital expenditures, and exit value. A cap rate is useful context, not a pass-or-fail rule.
How do I calculate cap rate on a property I already own?
Use current market value (not your purchase price) as the denominator. Your cap rate changes as the property appreciates even if NOI stays flat — this is how a property bought at a 7% cap can trade at 5% a few years later. Using purchase price gives you your original going-in cap rate; using current value gives you the current cap rate, which is what a buyer would pay today.
What's the difference between cap rate and gross yield?
Gross yield divides annual gross rent by purchase price — it ignores all expenses. Cap rate uses NOI after expenses, making it a far more useful comparison metric. A property with 10% gross yield and 50% expense ratio has a 5% cap rate. Gross yield is easy to calculate but can be misleading; cap rate is the standard professional metric for a reason.