Cap rates explained: the number that prices every building

What is a cap rate? The capitalization rate is a property's net operating income divided by its price — a 6% cap rate means the building produces $60,000 of NOI per $1,000,000 of value, before any mortgage. It is the yield the asset throws off if you paid cash, and it is how the entire commercial market communicates price: not in dollars, but in the relationship between dollars and income. Every valuation conversation you will ever have past the five-unit line happens in this language, and most of the expensive mistakes in real estate are cap-rate sentences misread.

The fraction, unpacked

NOI is all rental and other income minus all operating expenses — taxes, insurance, management, maintenance, reserves — but not mortgage payments, depreciation, or capital expenditures. That exclusion is the point: by stripping out financing, the cap rate lets a cash buyer, a 65%-leverage buyer, and a syndicator compare the same asset on the same basis. (Your levered return is a different number — see how to analyze a rental property for cash-on-cash and the rest of the metric stack.)

What the number is actually saying

A cap rate is the market's one-line risk memo. Class A multifamily in a growth metro trades at low caps because buyers accept a thin current yield in exchange for durable, growing income. A tired strip center in a shrinking town trades at a double-digit cap because buyers demand to be paid up front for income that may not persist. Institutional surveys — CBRE's cap rate survey is the standard reference — publish these spreads by asset class and market every six months, and the pattern never changes: the cap rate rises exactly where confidence in the income falls.

This is why "I only buy 10-caps" is not a strategy. In most markets, a 10-cap is a building where the market is telling you — loudly — that the NOI is about to shrink, the neighborhood is declining, or the expenses are understated. Sometimes the market is wrong, and that mispricing is the entire value-add business. But you have to know which sentence you're disagreeing with.

The lever that builds (and destroys) wealth

Run it backward and you have the risk: cap rate expansion. When rates rose in 2022–23, market caps moved up 100–150 basis points and multifamily values fell 20%+ with no change in the buildings themselves — the Fed's rate path repriced every income stream in the country at once. A buyer who underwrote an exit at the same cap they bought at had their entire projected profit erased by one assumption. The discipline: always model your exit cap higher than your entry cap — 50–75 basis points is a conventional margin — so cap-rate luck is upside, not load-bearing structure. This is the same humility that runs through market cycles: you control NOI; you do not control the multiple.

Where beginners misuse it

1. 01Trusting the listing's cap rateBroker pro formas routinely quote cap rates on projected rents and fantasy expenses (5% repairs, no management, last decade's tax bill). Recompute NOI from actuals — trailing twelve months, real tax reassessment at your purchase price, real insurance quotes — and watch a '7-cap' become a 5.4.
2. 02Using cap rates on 1–4 unit housesSmall residential is priced by comparable sales, not income — the cap rate of a single-family rental is trivia, not valuation. The metric earns its keep at five units and up, where appraisers actually use the income approach.
3. 03Comparing caps across markets or classesA 6-cap in Dallas and a 6-cap in a rural tertiary town are different risk universes at the same number. Cap rates only rank assets within the same market, class, and vintage.
4. 04Confusing cap rate with returnYour return depends on leverage, loan terms, NOI growth, and exit — the cap rate is just the sticker. A 5-cap with 4% annual NOI growth beats a static 7-cap over a hold, and the twenty-year math compounds that gap brutally.

The full metric stack: how to analyze a rental property. Where cap rates start mattering: the five-unit line. Using the multiplier deliberately: the value-add multifamily playbook.