What Is a Cap Rate? Definition, Formula, and Calculator

What Is a Cap Rate?

The cap rate measures how much annual profit you'll generate relative to your total investment. It answers the fundamental question: "What percentage return will I make on this property?"

Unlike stocks or bonds, real estate returns come from both rental income and property appreciation. The cap rate focuses purely on the income component, ignoring potential price growth. This makes it useful for comparing properties on a level playing field.

The Cap Rate Formula

Cap Rate = NOI ÷ Property Value

Where NOI (Net Operating Income) = Gross Rental Income − Operating Expenses

Operating expenses include property taxes, insurance, maintenance, property management fees, utilities (if you cover them), and vacancy allowance. It does not include debt service (mortgage payments) or capital gains.

Example: A $500,000 rental property generates $50,000 in gross annual rent. After $15,000 in operating expenses, NOI is $35,000. The cap rate is $35,000 ÷ $500,000 = 7%.

The NOI a Seller Shows You Is Almost Always Too High

Cap rate is only as honest as the NOI underneath it, and the two lines most often missing from a listing's pro forma are the two that never go away: vacancy and management. Here is the same $500,000 property, priced from a seller's numbers and then from realistic ones.

Nothing in the realistic column is pessimistic. A 5% vacancy allowance assumes the unit is empty about two and a half weeks a year. The management fee applies whether you hire a manager or do the work yourself — if you do it yourself, you have bought a job, and the 8% is your wage.

Then there is the line that sits outside NOI entirely: capital expenditure. Roofs, HVAC systems, water heaters and appliances are replacements, not operating expenses, so by convention they are excluded from NOI and therefore from the cap rate. They are not excluded from your bank account. Reserving 5% of gross rent — $2,500 a year here — drops the real cash yield before any financing to about 5.0%. A property advertised at a 7% cap is delivering five.

Rebuild the expense side yourself in the cap rate calculator using your own vacancy and management assumptions rather than the seller's, and compare that figure — never the listing's — against other deals.

What Makes a Good Cap Rate?

Cap rates vary dramatically by market, and the range runs in the opposite direction to what most people expect: the strongest markets have the lowest cap rates. Buyers accept less current income where they expect more appreciation and less vacancy risk. There's no universal "good" cap rate—it depends on your location, property type, and risk tolerance.

In low-yield markets (gateway coastal cities, strong job markets), cap rates are typically 3-5%. These markets offer appreciation potential and lower vacancy risk, compensating for lower income yields.

In secondary markets (mid-size cities, stable economies), cap rates typically range 6-8%. These offer better immediate returns with moderate appreciation potential.

In tertiary or higher-risk markets, cap rates can exceed 10%. Higher yields compensate for higher vacancy risk, thinner tenant demand and less predictable appreciation. A double-digit cap rate is not a bargain; it is the market pricing in something you should go and find.

A "good" cap rate means the property generates enough income to cover costs while meeting your required return. Most real estate investors target cap rates of at least 5-8%, though this varies by market and strategy.

Cap Rate vs. Cash-on-Cash Return

These are often confused but measure different things. Cap rate divides NOI by the full purchase price and ignores the loan entirely. Cash-on-cash divides the cash left after the mortgage by the cash you actually put in — and that difference is where most beginner analyses go wrong.

Example, done properly. A $500,000 property with $35,000 of NOI has a 7% cap rate. You put $100,000 down and borrow $400,000 on a 30-year loan at 7%. Annual debt service on that loan is about $31,933.

• Cash flow after debt service: $35,000 − $31,933 = $3,067
• Cash-on-cash return: $3,067 ÷ $100,000 = 3.1%

Not 35%. Dividing NOI by the down payment without subtracting the mortgage is the single most common error in rental analysis, and it makes every leveraged deal look roughly ten times better than it is.

Now redo it with the realistic $27,700 NOI from the table above: $27,700 − $31,933 = −$4,233 a year. The property loses money every month, on a 7% advertised cap rate, at a conventional 20% down.

Negative Leverage: When the Mortgage Costs More Than the Property Earns

The reason that deal fails has a name. Compare the cap rate to the loan constant — annual debt service divided by the loan balance. Here it is $31,933 ÷ $400,000 = 7.98%.

• Cap rate above the loan constant → positive leverage. Borrowing amplifies your return; more debt is better.
• Cap rate below the loan constant → negative leverage. Every borrowed dollar earns less than it costs, and more debt makes the return worse.

At a 7.0% cap against a 7.98% constant, this deal has negative leverage before you even correct the NOI. That relationship, not the cap rate on its own, is what determines whether a mortgage helps you.

Your lender is running a version of the same test. Debt service coverage ratio is NOI divided by annual debt service: $27,700 ÷ $31,933 = 0.87. Commercial and DSCR lenders typically want at least 1.20 to 1.25, so this property would not qualify at these terms — check the DSCR your numbers produce before you assume the financing exists. If the deal only works at a lower rate or a larger down payment, that is worth knowing before the appraisal, not after.

This is also why cap rates are better for comparing across deals — they remove financing from the equation, so two properties are measured on the same basis. Just never mistake a comparison tool for a return.

Cap Rate Limitations

Cap rates only measure current income yield. They ignore:

• Appreciation potential: A property in a hot market may have a low cap rate but high appreciation
• Financing impact: Two identical properties can produce different actual returns depending on mortgage terms
• Expense estimates: Cap rates are only as accurate as your NOI assumptions
• Risk variations: Two properties with identical cap rates may have very different vacancy risks

Cap rates are a starting point, not the entire investment decision. Always analyze local market trends, property condition, tenant quality, and your personal investment timeline alongside cap rate.

How Investors Use Cap Rates

Comparing properties: A 7% cap rate in one market can be compared directly to a 7% cap rate anywhere else. This standardization lets you evaluate opportunities across different cities and price points.

Initial screening: Cap rate helps identify which deals might be worth deeper analysis. Deals below your minimum required cap rate can be eliminated quickly.

Valuation check: If you know the local cap rate for a property type, you can estimate its likely purchase price by dividing NOI by the cap rate. If a seller is asking way more than comparable cap rates suggest, it's overpriced.

Tools to Calculate Cap Rate

Use our Cap Rate Calculator to screen properties on a like-for-like basis. Then, because cap rate deliberately ignores your loan:

• Real Estate ROI Calculator — full projections including financing, cash-on-cash and total return
• DSCR Loan Calculator — whether the property's income supports the debt a lender will actually write
• BRRRR Strategy Calculator — for buy-rehab-rent-refinance deals, where the cap rate you buy at and the cap rate you refinance at are different numbers

Frequently Asked Questions

Q: Is a 5% cap rate good? A: It depends on your market. In coastal markets, 5% is above average. In secondary markets, it's below average. Compare against other properties in your target area.

Q: Does cap rate include mortgage payments? A: No. Cap rate uses NOI before any debt service, making it independent of how you finance the property. This lets you compare properties regardless of financing.

Q: What's the difference between gross yield and cap rate? A: Gross yield is annual rent divided by property price. Cap rate is NOI (rent minus expenses) divided by property price. Cap rate is more accurate because it accounts for real costs.

Q: Can cap rate predict appreciation? A: No. Cap rate only measures income. A low-cap-rate property in an appreciating market may still be an excellent investment—just not for income. Research local market trends separately.

Q: My cap rate is higher than my mortgage rate. Does that mean leverage helps? A: Not necessarily — compare it to the loan constant, not the interest rate. The constant is annual debt service divided by the loan balance, so it includes principal repayment as well as interest. A 30-year loan at 7% has a constant near 8%, so a 7.5% cap rate looks like positive leverage against the interest rate and is actually negative leverage against the constant. Shorter amortisation raises the constant further, which is why a 15-year loan can turn a workable deal into a cash-flow-negative one at the same interest rate.

Q: Where does cap rate stop working entirely? A: Three places. Owner-occupied property has no NOI, so there is nothing to divide. Short-term rentals swing so much on occupancy and cleaning costs that a single annual NOI figure hides the whole risk. And a vacant or heavily under-rented building has a meaningless current cap rate — those trade on stabilised or pro forma NOI, which is a forecast, and forecasts are where deals go wrong.

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