The cap rate formula is the smallest piece of arithmetic in commercial real estate, and it’s the one analysts get into the most arguments about.
Not because the math is hard. NOI divided by price equals cap rate. A high school student can do that. The arguments happen because the formula has three variables, all of them disputable, and the broker’s version of each variable tends to flatter the asset.
I spent 10 years on the buy side at Stockbridge Capital, the last five as Director of Research, and the cap rate formula appears on every deal screen, every IC memo, and every offering memorandum we ever touched. What follows is the formula in all three directions, with worked CRE examples — and then the part most articles skip, which is why the simple formula keeps producing the wrong number when the NOI input is wrong.
The cap rate formula
Cap Rate = Net Operating Income / Property Value
Or, written more cleanly:
Cap Rate = NOI / Price
Both sides are annual. NOI is annual net operating income — revenue minus operating expenses, before debt service, capital expenditures, depreciation, and income taxes. Property value is either the purchase price (for a closed transaction or an active deal) or an appraised market value (for a re-underwriting, refinancing, or annual valuation).
The result is expressed as a percentage. A property producing $1,000,000 of NOI valued at $15,000,000 has a cap rate of:
$1,000,000 / $15,000,000 = 0.0667 = 6.67%
That is the entire formula. The rest of this guide is about the three directions you can use it and the four ways the inputs go wrong.
Direction 1: Solving for the cap rate
This is the standard use. You know the NOI. You know the price. You want the cap rate.
Worked example: stabilized industrial in a primary submarket
A 220,000 SF Class A distribution warehouse is on the market. The OM shows:
| Line Item | Amount |
|---|---|
| Base Rental Income | $2,420,000 |
| Reimbursements (NNN) | $660,000 |
| Total Revenue | $3,080,000 |
| Vacancy & Credit Loss (2%) | ($61,600) |
| Effective Gross Income | $3,018,400 |
| Operating Expenses | ($720,000) |
| Real Estate Taxes (passed through) | $0 |
| Net Operating Income | $2,298,400 |
Asking price: $42,500,000.
Cap Rate = $2,298,400 / $42,500,000 = 5.41%
For a primary-market Class A NNN industrial asset in 2026, 5.41% is in the expected band. Whether it’s the right number depends on the lease structure, the tenant credit, the rent versus market, and the remaining lease term — none of which the formula cares about.
This is the version brokers use to quote the asset. It’s also the version they massage by selectively choosing which expenses to include in operating expenses, what vacancy factor to apply, and whether to include or exclude reimbursements net of recoveries.
Direction 2: Solving for value
You know the NOI. You know the market cap rate from comparable transactions. You want the implied value.
Cap Rate Formula (rearranged): Value = NOI / Cap Rate
Worked example: multifamily refinancing
A 240-unit garden-style multifamily asset in a Sun Belt submarket is up for refinancing. The trailing 12-month NOI, properly normalized, is:
| Line Item | Amount |
|---|---|
| Gross Potential Rent | $5,184,000 |
| Loss to Lease | ($103,680) |
| Vacancy (5%) | ($259,200) |
| Concessions & Bad Debt | ($129,600) |
| Other Income (RUBS, fees) | $480,000 |
| Effective Gross Income | $5,171,520 |
| Operating Expenses | ($2,068,608) |
| Replacement Reserves ($300/unit) | ($72,000) |
| Net Operating Income | $3,030,912 |
Recent comparable trades in the submarket cleared at 5.25-5.50% on similar-quality assets. The appraiser uses 5.40% as the market cap rate.
Value = $3,030,912 / 0.0540 = $56,128,000
That’s the income approach to valuation, and it’s how the appraisal industry derives most institutional-grade valuations. The lender uses this number to size the loan. The owner uses it to decide whether to refinance, recapitalize, or sell.
The output is only as good as the comparable cap rates used as inputs. If the most recent comp is six months stale and cap rates have moved 50 bps, the appraised value will be wrong by approximately 10%.
Direction 3: Solving for implied NOI
This direction is less common but useful in two situations: when a broker quotes a cap rate without breaking out the NOI build, and when you want to reverse-engineer what NOI the seller’s price implicitly assumes.
Cap Rate Formula (rearranged): NOI = Price x Cap Rate
Worked example: figuring out what the broker is asking you to underwrite
A broker pitches a suburban office building at $32,000,000 and quotes a “6.5% cap rate.” They don’t share a clean NOI breakdown — just a teaser. You want to back into the implied NOI to gut-check whether the asset can plausibly produce that number.
Implied NOI = $32,000,000 x 0.065 = $2,080,000
Now divide that by the building’s 165,000 SF: $2,080,000 / 165,000 = $12.61/SF of NOI.
For a Class B suburban office building at 80% occupancy with $24/SF gross rents and a 50% expense ratio, that NOI is achievable only if every lease is at market, vacancy holds, and operating expenses don’t grow. In other words, the cap rate is real only if the broker’s NOI assumptions are correct — which on a suburban office building in 2026, they usually aren’t.
This is one of the fastest ways to pressure-test a quoted cap rate: derive the implied NOI, divide by SF, and compare against what you know the building can realistically produce.
Why the formula is simple but the NOI calculation is where deals go wrong
The cap rate formula has three variables. In a typical disputed deal, all three are wrong, but the most damaging errors live in the NOI line. Here’s what to watch.
Trailing vs. forward
Trailing 12-month NOI is what the property has actually produced. Forward 12-month NOI is what it’s projected to produce. They are different numbers — sometimes very different.
On a leasing-up asset, forward NOI is higher than trailing because new tenants are coming online. The broker quotes the forward NOI to make the cap rate look more attractive.
On a leasing-down asset (lease expirations exceeding renewals), forward NOI is lower than trailing. The broker quotes the trailing NOI to make the cap rate look more attractive.
In both cases, the broker is picking the number that supports their narrative. The buyer needs to compute both and underwrite against the one that reflects reality during the hold period.
Normalization adjustments
Off the top, raw operating statements typically need adjustments before they belong in an NOI calculation:
- Vacancy and credit loss. Use market-level, not the seller’s optimistic number. If submarket vacancy is 11%, do not let 4% vacancy flow into your underwriting just because the building’s leases are currently full.
- Management fees. Even if the seller is self-managing at zero cost, a buyer needs to assume a market management fee — typically 3-4% of EGI for industrial and office, similar for multifamily.
- Replacement reserves. Often excluded from broker NOI. Real buyers include them. Multifamily reserves run $250-400/unit/year; industrial and office run $0.15-0.50/SF.
- Real estate taxes. If the seller has held the asset for years and has a frozen or under-assessed tax basis, the buyer’s tax bill at the new purchase price will be materially higher. Underwrite the post-acquisition tax bill, not the seller’s.
- Repairs vs. capital. Sellers sometimes classify capital projects as operating repairs to inflate NOI. Pull out the GL detail and reclassify anything that is capital in nature.
These adjustments together can move NOI by 5-20% on a typical deal. Apply them before you run the cap rate formula, not after.
What counts as NOI
Different sub-asset classes have conventions. Hotels deduct a 4% FF&E reserve and management fees as part of NOI because both are real operating costs. Multifamily includes other income (RUBS, parking, pet rent, application fees) but excludes laundry concession overrides. Retail includes percentage rent only when it’s contractually triggered by sales performance, not as a projection.
Mixing conventions across deals or asset classes produces inconsistent cap rates. A buyer underwriting multifamily and retail in the same fund needs to know that each asset class has its own definition of what belongs in NOI.
Lease abstraction quality
This is where most of the deal errors I’ve seen actually originate. The rent roll says one number. The leases say something slightly different — a step rent that’s about to kick in, a free rent period that’s not yet expired, an unfunded TI allowance that reduces effective rent, a co-tenancy provision that reduces rent if a specific anchor leaves.
If those terms aren’t pulled accurately from the leases into the rent roll, the NOI is wrong, the cap rate is wrong, and the price the buyer pays is wrong. This is the bottleneck the DDee.ai platform is designed for: structured extraction of every lease term with a confidence-scored citation back to the source PDF, then a tenant-by-tenant reconciliation against the rent roll. Errors that historically took days of analyst time to catch get surfaced as findings in the IC-ready package.
The formula is trivial. The NOI is the work.
How the cap rate formula relates to other valuation metrics
The cap rate is one of three primary valuation approaches in CRE. Each handles the relationship between income, value, and risk differently.
Direct capitalization. This is the cap rate formula. One year of NOI capitalized at a market rate. Fast, transparent, comparable across deals, but contains all growth and risk assumptions implicitly inside the rate itself.
Discounted cash flow. Multi-year projection of NOI, sale proceeds, and capital outflows discounted back to present value at a chosen discount rate. Handles growth, capital, and exit assumptions explicitly. More precise, harder to build correctly, and considerably easier to manipulate. Argus is the dominant modeling tool. The DCF is where IRR comes from.
Sales comparison approach. Recent transactions on similar assets, adjusted for differences. Less reliant on assumptions, more reliant on the quality of the comp set. Often used as a sanity check on the income approach.
In practice, a thorough valuation uses all three and triangulates. The cap rate formula is the fastest of the three but also the most assumption-laden once you get past the surface arithmetic. A 7% cap and a 5% cap on the same asset can both be defensible depending on which NOI you choose to put in the numerator.
That’s the formula. Treat the arithmetic as trivial. Spend the time on the NOI.