What Is Cap Rate in Real Estate, and What Counts as Good

If you spend any time around real estate investors, you hear one number thrown around more than any other. What's the cap rate? It's the first question a serious buyer asks about an income property, before square footage, before the neighborhood, before the color of the kitchen. And for good reason. It compresses a whole deal into a single percentage you can compare against every other deal on the table.

Here's the whole thing in one line. Cap rate is net operating income divided by price.That's it. It tells you the annual return you'd earn if you bought the property in cash, before any loan, before taxes on your income, before anything clever. The way I think about it, cap rate is the price tag written in the language of yield instead of dollars, and once you can read it, you stop overpaying.

The formula, and why it's so useful

Cap rate, short for capitalization rate, is defined as annual net operating income divided by the property's current market value or purchase price.^[1] Multiply by 100 to get a percentage. A building throwing off $60,000 of NOI that sells for $1 million has a 6% cap rate. If that same $60,000 building sells for $750,000, the cap rate jumps to 8%. Same income, lower price, higher yield. Price and cap rate move in opposite directions, which is worth burning into memory.

The reason cap rate earned its status is that it strips a deal down to comparable form. A fourplex in one city and a strip mall in another have nothing obvious in common, but their cap rates sit on the same scale. You can line up ten properties, glance at ten percentages, and instantly see which ones the market is pricing as safe and which as risky. That's a lot of signal from one division problem.

How to calculate NOI, and what you must leave out

The cap rate is only as honest as the NOI you feed it, so this is where people get fooled. Net operating income is your gross rental income, plus any other property income like parking or laundry, minus all operating expenses.^[2] Operating expenses means property taxes, insurance, maintenance and repairs, property management, utilities you cover, and a realistic vacancy allowance because no building is full every single month.

Now the part that trips everyone up. NOI deliberately excludes several big costs. It does not subtract your mortgage payment. It does not subtract income taxes. It does not subtract depreciation, and it does not subtract big capital expenditures like a new roof or HVAC system.^[2]Leaving out the mortgage is the important one. It's not an oversight, it's the entire point. By ignoring financing, NOI describes the property itself, so two buyers using totally different loans still see the same NOI and the same cap rate on the same building.

What high vs low cap rates actually signal

This is where beginners get it backwards. A high cap rate is not automatically a better deal, and a low one is not automatically a rip-off. The cap rate is the market pricing risk. A low cap rate, say 4%, usually means a high-demand, low-risk location where buyers are happy to accept a smaller yield because they trust the income is stable and the property will hold or grow in value.^[3] Think prime urban apartments in a growing metro.

A high cap rate, say 9%, is the market demanding more yield to compensate for something. Maybe it's a weaker local economy, a declining population, an older building, or a tenant base that turns over constantly. The extra return isn't free money. It's the price of risk you're being paid to take.^[3]Sometimes that trade is great. Sometimes you're catching a falling knife in a town that's emptying out. The number alone can't tell you which.

This is the same logic that runs through whether buying a house is actually a good investment. Price is never just price. It bakes in the market's collective read on risk, growth, and demand, and your job as a buyer is to decide whether you agree with that read or think the crowd has it wrong.

A worked example, start to finish

Let's put real numbers on it. Say you're looking at a small apartment building listed at $1,000,000. It brings in $96,000 a year in gross rent. You expect a 5% vacancy loss, so knock off $4,800, leaving $91,200 in collected income.

Now the operating expenses. Property taxes run $12,000. Insurance is $4,000. Maintenance and repairs, budget $8,000. Property management at 8% of collected rent is about $7,300. Utilities and common-area costs, $3,000. Add those up and you get roughly $34,300 in operating expenses. Subtract that from your $91,200 and your NOI is about $56,900.

Cap rate is $56,900 divided by $1,000,000, which is 5.7%. That's the property's unleveraged yield. Notice the mortgage never entered the math. Whether you pay all cash or put 25% down, the cap rate on this building is 5.7%, because cap rate is a fact about the property, not about your bank.

Cap rate vs cash-on-cash return

Here's the number cap rate can't tell you, and it's the one that hits your bank account. Cap rate assumes an all-cash purchase. Cash-on-cash return measures the actual return on the cash you personally put into the deal after financing.^[4] Since almost nobody buys rentals in cash, this second number is what you actually live on.

Back to our building. Say you put 25% down, $250,000, and borrow $750,000. Your annual mortgage payment, principal and interest, might run around $54,000 depending on the rate. Your NOI was $56,900, so after debt service you're left with about $2,900 of pre-tax cash flow. Divide that by your $250,000 invested and your cash-on-cash return is roughly 1.2%. The same building had a 5.7% cap rate and a 1.2% cash-on-cash return. Both true, both measuring different things.

That gap is leverage at work. When your loan rate is below the cap rate, borrowing amplifies your return in your favor. When your borrowing cost is above the cap rate, as in this example, leverage works against your cash flow. This is exactly why the numbers behind how much landlords actually make vary so wildly between two people who bought identical buildings. Same cap rate, completely different financing, completely different outcome.

How interest rates move cap rates

Cap rates don't float in isolation. They track interest rates, and understanding why is what separates people who buy at the top from people who wait. When the Federal Reserve pushes rates up, two things happen at once. Borrowing gets more expensive, and safe alternatives like Treasury bonds start paying more.^[5] A 10-year Treasury yielding 4.5% sets a floor. Why would anyone accept a 4% property yield, with all the headaches of tenants and toilets, when a risk-free bond pays more?

So they don't. Buyers demand a higher cap rate to make the risk worth it, and the only way to raise the cap rate on a building with fixed rent is to pay less for it. Rates up, cap rates up, prices down. It's not a perfect one-to-one relationship, because rent growth and local demand push back, but the gravity is real.^[6] The spread between cap rates and the 10-year Treasury is one of the most watched numbers in commercial real estate for exactly this reason.

My take: stop chasing the highest cap rate

Here's the opinion I'll plant a flag on. New investors fixate on finding the highest cap rate they can, as if 9% is automatically twice as good as 5%. That's backwards, and it's how people end up owning cheap buildings in dying towns. A cap rate is a risk-adjusted number. The high ones are high because the market has already priced in problems you may not see yet: soft demand, deferred maintenance, a tenant base one layoff away from vacancy.

The cap rate you should want is the one that fairly pays you for a risk you actually understand and are equipped to manage. A 5.5% cap rate in a growing metro with rising rents can crush a 9% cap rate in a shrinking one, because appreciation and rent growth show up in your total return and never appear in the cap rate at all. Cap rate is a snapshot. It says nothing about where the picture is heading.

So use cap rate the way it's meant to be used. As a fast, honest first filter to compare deals and sanity-check a price, not as a scoreboard where the biggest number wins. Rebuild the NOI yourself so the cap rate is real. Then run the cash-on-cash return to see what you actually take home, and think hard about which direction the market and the rent are moving. If you're still deciding whether to be in this game at all versus just owning a home you live in, that's a different calculation, and it's the one I work through in renting vs buying a home. The best deal is rarely the one with the flashiest cap rate. It's the one where you understood exactly what you were being paid to take on.