What Is a Cap Rate? The Price the Market Puts on Income

Of the two numbers that set a building’s value, the cap rate is the one an operator does not control, and it moves that value more than anything the operator does.

Most explanations of the cap rate stop at the formula, and the formula is trivial. What makes the cap rate worth understanding is that it behaves like a yield but functions like a price, and it is set by forces outside the building: where interest rates sit, how much risk the market sees in the asset, and how fast buyers expect the income to grow.

What is a cap rate?

A cap rate is a property’s net operating income divided by its value: NOI ÷ value. Read one way it is a yield, what the building returns each year on its price if it were bought for cash. Flipped over, it becomes a multiple, and answers the only question a buyer really cares about: how much to pay for a stream of income.

It is the same idea as a price-to-earnings ratio, turned upside down. A cap rate is the inverse of a P/E multiple: where a stock trading at 20 times earnings has a 5 percent earnings yield, a building bought at a 5 percent cap rate trades at 20 times its NOI. That inversion is why real estate uses cap rates at all: it lets an investor line up the yield on a building against the yield on a bond or a Treasury. Listed REITs get judged the same way, on the income they throw off.

One point trips up almost everyone new to it: a lower cap rate is good news for an owner, not bad. Because the cap rate is NOI over value, the lower it goes, the more value sits under every dollar of income. A building whose NOI holds steady while its cap rate falls from 6 percent to 5 percent just became worth 20 percent more, with nothing changing inside the building at all.

Few numbers in real estate get more attention. Brad Hargreaves, founder of Thesis Driven, recalls that early in his career, “the biggest event for real estate professionals in New York was an event called Coffee and Cap Rates,” a standing monthly gathering. That fixation is rational: the cap rate is the market’s running verdict on whether a building is cheap or expensive.

The cap rate formula, and how to calculate it

The math runs in both directions, which is the whole point. A building throwing off $1 million of NOI, bought at a 5 percent cap rate, is worth $20 million: one million divided by 0.05. Flip it, and a known sale reveals the cap rate: a $20 million building with $1 million of NOI traded at a 5 cap. The net operating income on top of the fraction has to be a clean, stabilized annual number, which is where most of the real work sits. Valuing a building this way, income divided by a market cap rate, is what appraisers call direct capitalization.

Thinking in the multiple, rather than the rate, keeps the stakes visible. A 5 cap is a 20 times multiple; a 4 cap is 25 times. That one point of cap rate, from four to five, is the difference between paying 25 times NOI and paying 20, and the gap is not linear: the move from a 5 to a 6 cap is smaller than the move from a 4 to a 5. When a broker quotes an asset “in the high fours,” meaning a cap rate around 4.7 or 4.8 percent, that quarter-point is doing more work than it looks.

The one label worth knowing is the going-in cap rate: year-one NOI divided by the purchase price, sometimes called the year-one NOI yield. Watch the denominator, because some buyers quote it on the price alone and others on the price plus closing costs (an “all-in” going-in cap), and the two are not the same number.

What drives cap rates

Cap rates move with three things, and none of them are the building’s own operations.

Asset type sets the baseline: apartments trade at lower cap rates than office, retail, or industrial, because a single vacancy or tenant bankruptcy is far less likely to sink an apartment building than a single-tenant office or store. The ranking is not fixed: industrial cap rates compressed over the last decade as e-commerce, logistics demand, and reshoring made the space more wanted, while retail cap rates spiked through the pandemic and the rate-hike cycle as the market priced in more risk, the kind of sector shift PwC’s Emerging Trends in Real Estate tracks year to year.

Interest rates matter too, though the relationship is looser than it is often made out to be. The usual logic is competition: when treasuries yield more, a cash-flowing building has to offer more to compete, so cap rates tend to drift up, meaning fewer dollars of value for every dollar of NOI. That is why investors think of a cap rate as a premium over the risk-free rate, the extra yield real estate has to pay for taking real risk. But rates are only one input, and rarely the decisive one. Rising rates were part of the cap-rate increases of 2022 and 2023, not the whole story; cap rates are pushed at least as much by the market’s appetite for risk and the amount of capital chasing deals, which is why they do not track treasuries one-to-one and why large institutions keep allocating to real estate across rate cycles.

Risk and growth do the rest: an asset earns a lower cap rate if the market believes its income will grow or sees it as low-risk. The formal version is the Gordon growth model, where the cap rate equals the discount rate minus the expected NOI growth rate, so faster-growing income supports a lower cap rate and a higher price. It is why a stabilized apartment building in a supply-constrained market trades at a lower cap rate than an aging strip center with flat rents.

What counts as a “good” cap rate?

There is no universal good cap rate, because it is a relative number, not an absolute one. A low cap rate is good for an owner, since it means a high price for the income; a high cap rate is good for a buyer, since it means more yield for less money. The same 5 cap that thrills a seller is the one a buyer wants to push higher.

The honest way to judge one is against the risk-free rate and the asset’s risk: a cap rate only a hair above the ten-year treasury is pricing in almost no risk, which may or may not be deserved. Market context moves constantly, quality multifamily has traded roughly in the high-fours to low-fives, call it 4.5 to 5.5 percent, in the mid-2020s, per cap-rate trackers like Green Street, but that number is a snapshot, not a rule, and the right way to pin it down is to ask brokers and read the cap-rate research firms like JLL publish. In practice cap rates get quoted in quarter-point steps; nobody underwrites to a 5.13.

Going-in vs exit cap rate: underwriting the sale

A deal has two cap rates that matter: the going-in cap it is bought at, and the exit cap assumed at sale. The exit is the one that keeps sponsors up at night, because it is a guess about the market years out. Valuing an asset at the end of a five-year hold means dividing its year-six NOI by that assumed exit cap; the number a sponsor picks is, in the honest words of the course, a finger in the air.

Two assumptions pull in opposite directions. Cap rate expansion is the conservative move: assume a sale at a slightly higher cap than the purchase, often five to ten basis points a year, on the logic that the building will be older and a little riskier at exit. Cap rate compression is the aggressive one: assume a sale at a lower cap than the purchase. Compression is where fortunes have been made, because when the cap rate falls over the hold, the multiple expands and returns can climb dramatically, but it is a bet on the market, not on anything the operator builds.

That bet is the most sensitive assumption in the whole model. Off by 25 basis points on the exit cap and a deal misses its target materially; let the exit cap drift a point or more the wrong way and a sponsor’s promote can vanish while every operating number came in exactly as planned. Harbor Yards, the mixed-use case Thesis Driven teaches in its Fundamentals of CRE course, shows the mechanic cleanly: $8.5 million of NOI at an assumed 5 percent exit cap is a $170 million sale, and shifting that cap even slightly rewrites the outcome. The last cycle made the point twice over: compression bailed out buyers who missed every operating metric, and expansion punished operators who hit all of theirs.

When the cap rate lies

The cap rate is a shorthand, and like any shorthand it breaks in specific, knowable places. It values a stabilized asset, one at steady occupancy and income. Apply a stabilized cap rate to a building that is half-leased or mid-renovation and the math undervalues it, because the depressed near-term NOI is not the income the asset will actually produce. For value-add or non-stabilized deals, the cap rate is the wrong tool and a discounted cash flow is the right one.

Two more traps hide in how cap rates are quoted. A nominal cap rate uses raw NOI; an economic cap rate first subtracts capital reserves, so the two describe the same building with different numbers, and comparing one to the other is apples to oranges. And cap rates pulled from comparable sales are shakier than they look: the sale price is public, but the NOI behind it usually is not, so a “reported” cap rate is often someone’s estimate. The reliable ones come from brokers who were in the room, or from return datasets like NCREIF.

None of this makes the cap rate less important. It makes it the number to interrogate hardest, because it is set outside the building and moves value more than operations do. The operators who compound through a cycle treat their exit cap as a bet to stress-test, not a given to plug in.

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Related reading:

• Net Operating Income (NOI): An Operator’s Guide
• Real Estate Pro Forma: An Operator’s Guide
• Seven Real Estate Predictions for 2026