What it means
Net operating income is rental income after allowing for empty units and after the day to day costs of running the building, but before mortgage payments, income tax and depreciation. Stripping out financing is deliberate, because it lets you judge the asset itself rather than the particular deal someone has structured around it.
A higher cap rate means more income per dollar of price, which usually signals either a bargain or a riskier asset. Prime offices in a major city might change hands on a 4% to 5% cap rate, while a tired industrial shed in a small town might need to offer 9% or more before anyone will look at it.
Cap rates are used in three ways: to price a purchase, to value a building you already own, and to sanity-check a market. Turn the formula around and you can value almost any property by dividing its income by the cap rate that comparable buildings are trading at.
The rate moves inversely to value, which regularly trips people up. If the market cap rate rises from 6% to 7% while your building's income stays flat, the building is worth roughly 14% less, and nothing about the tenant, the location or the roof has changed.
The nuance to watch is what goes into net operating income. Sellers love to quote a cap rate built on full occupancy, optimistic rents and no allowance for replacing the lift, so a careful buyer's own cap rate on exactly the same building is often a full percentage point lower.
In practice
Real-world examples
Example 1
A dental practice owner is offered the building she rents for $1,850,000. Its net operating income after all running costs is $148,000, giving a cap rate of exactly 8%, and because similar suburban units in her town trade between 7% and 8%, she treats the price as fair rather than a bargain.
Example 2
A logistics business considers selling its warehouse and leasing it back. Its agent explains that investors are pricing that class of building at a 6.5% cap rate, so the $520,000 of rent the business would commit to paying implies a sale price near $8,000,000, which reframes the decision as a financing choice rather than a property one.
Example 3
A regional council reviewing land values notices that local cap rates on mixed-use blocks have moved from 5.5% to 6.5% in eighteen months. Rents have not fallen, so the council concludes that buyers are simply demanding more return because borrowing has become more expensive.
Think of it
Cap rate is the yield on real estate-income relative to price.
Formula
Calculation
Cap Rate = Net Operating Income / Property Value
Consider a small retail parade on the market at $6,000,000.
Gross potential rent if every unit is let: $750,000.
Less vacancy and credit loss at 5%: $37,500.
Effective gross income = $750,000 - $37,500 = $712,500.
Less operating expenses (rates, insurance, repairs, management, common area costs): $232,500.
Net operating income = $712,500 - $232,500 = $480,000.
Cap Rate = $480,000 / $6,000,000 = 8%.
Now run it backwards. A buyer who insists on a 9% return would only pay $480,000 / 0.09 = $5,333,333, roughly $667,000 less than the asking price. A seller who could raise net operating income to $540,000 through a rent review would, at the same 8% market rate, justify a value of $540,000 / 0.08 = $6,750,000. Small movements in either number swing the price by hundreds of thousands of dollars.Case study
Seen in the real world
Harbour Lane Property Partners is an illustrative, invented investor used to show how cap rates behave when interest rates move. In this fictional example the firm bought a four-unit office building for $6,000,000 on an 8% cap rate, funded with $3,600,000 of debt at a fixed rate for five years.
Three years later the tenants were all still in place and net operating income had risen slightly to $498,000. Yet when Harbour Lane tested the market, agents quoted a 9.5% cap rate for that type of building because borrowing costs across the sector had risen sharply. The implied value was $498,000 / 0.095 = $5,242,105, well below the purchase price, despite a stronger income line.
The illustrative lesson is that a property investor can do everything right at the building level and still lose value, because the cap rate is set by the capital market rather than the tenant. Harbour Lane chose to hold, refinance later, and focus on lifting rents so that income growth could offset part of the higher rate whenever it eventually sold.
Watch out
Common mistakes
- Including mortgage interest in net operating income. Cap rate is meant to describe the asset independently of how it is funded, and adding debt costs makes two identical buildings look different.
- Assuming a high cap rate is always a better deal. A 12% cap rate usually means a short lease, a weak tenant or a building that needs capital spending soon.
- Using the seller's stated income without adjusting it. Vacancy allowance, management fees and a reserve for major repairs are frequently missing from marketing material.
Questions
People also ask
Does cap rate account for growth?
No, it is a snapshot of one year's income against price, so a building with strong rent growth prospects can justify a lower cap rate than the number alone suggests.
What is the difference between cap rate and yield?
In everyday use they are often the same thing, though yield is sometimes quoted on gross rent rather than net operating income, which produces a flattering and less comparable figure.
Can cap rate be used on anything other than property?
It is occasionally applied to other income-producing assets such as car parks or storage sites, but it is not a sensible measure for a trading business whose earnings depend on operations rather than a lease.
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