By Novo Real Estate
Cap rate is the closest thing commercial real estate has to a common language. One number lets us put a Mission mixed-use building and a Sunset multi-family property side by side and compare what each returns relative to what it costs. We treat it as the opening question in a search rather than the closing one, which is exactly what makes it useful. Here's how to calculate it and how to read it in San Francisco.
Key Takeaways
- Cap rate equals net operating income divided by purchase price or current market value.
- NOI counts operating expenses and leaves out debt service, so cap rate describes the property rather than your financing.
- Cap rates move by asset class as much as by geography, and San Francisco's classes have diverged in recent years.
- On rent-controlled San Francisco units, the allowable annual increase is 1.6% from March 1, 2026 through February 28, 2027.
How Do You Calculate a Cap Rate?
Cap rate is net operating income divided by the purchase price or current market value, expressed as a percentage. A building producing $200,000 of NOI at a $4,000,000 price carries a 5% cap rate.
The arithmetic is simple, so all the work sits in the NOI. Build that number carefully, and the cap rate starts telling you something real about the asset.
What Goes Into NOI
- Effective gross income — all rent collected plus other income like parking or laundry, after allowing for vacancy.
- Operating expenses subtracted — property management, maintenance, insurance, and property taxes.
- Debt service excluded — a mortgage sits outside NOI, which is what lets two different buyers compare the same building.
- Capital expenditures excluded — a roof replacement is a capital item rather than an operating expense.
Why Does Cap Rate Matter to Investors?
Cap rate matters because it standardizes properties that otherwise resist comparison. Different sizes, different unit counts, different neighborhoods, and one ratio that puts them all on the same axis.
The reverse calculation is where we get the most use out of it. It turns a submarket's trading data into a valuation tool you can apply to any building's income.
What the Number Gives You
- A shortlist, fast — a quick read on whether an asking price sits in line with comparable sales nearby.
- A supportable valuation — dividing NOI by a market cap rate produces a defensible estimate of value.
- A conversation starter with lenders — it's the metric most underwriters open with.
- A bridge to your own returns — most investors move from cap rate to cash-on-cash once financing enters the picture.
What Affects Cap Rates in San Francisco?
Asset class, location, building condition, and the interest rate environment all move cap rates, and asset class is doing the most work in San Francisco right now. The city's property types have moved on separate tracks in recent years rather than together.
Stabilized multi-family and retail here have held to the compressed yields long associated with established coastal markets. Office has repriced toward notably higher cap rates over the same period, which is why buyers with an office thesis are finding San Francisco interesting again.
The Local Inputs
- Which asset class you're in — the spread between property types in San Francisco is currently wider than the spread between many cities.
- Rent regulation on covered units — the San Francisco Rent Ordinance sets an allowable annual increase, currently 1.6% for the year beginning March 1, 2026, up from 1.4% the prior year.
- Submarket demand — neighborhood-level rent and vacancy patterns move NOI far more than citywide averages do.
- Financing conditions — the prevailing rate environment shapes what buyers will pay for a given income stream.
What Should You Do With the Number?
Use the cap rate to build a shortlist, then verify the inputs underneath it. A published cap rate rests on the seller's expense assumptions, and confirming those is where a good deal usually proves itself.
That verification is most of what we do in the first week on a property. Once the income and expenses hold up, the conversation moves to financing, business plan, and hold period.
How We'd Work Through It
- Confirm the rent roll — actual collected rent, current lease terms, and which units are regulated.
- Rebuild the expenses — taxes, insurance, management, and maintenance from real figures.
- Compare against verified comps — recent sales of similar assets in the same submarket, not citywide averages.
- Layer in your financing — cap rate describes the property, so cash-on-cash return is what describes your deal.
Frequently Asked Questions
What is a good cap rate?
We'd say it depends on the asset class, the market, the building's condition, and the rate environment. A stabilized building in an established coastal market typically trades at a lower cap rate than a value-add property elsewhere, and we've seen both make excellent buys.
Does cap rate include your mortgage?
No, and that's the point of it. NOI excludes debt service, so we can use cap rate to describe a property's performance independent of how any particular buyer finances it.
What's the difference between cap rate and cash-on-cash return?
Cap rate measures income against the property's value, and cash-on-cash measures income against the actual cash you put in. We look at both, since the second one reflects your financing while cap rate doesn't.
Reach Out to Novo Real Estate Today
Cap rate is the fastest way to build a shortlist and the fastest way to get comfortable in a market you're new to. Confirming the numbers underneath it is where the opportunity usually shows up.
We analyze cap rates, zoning, and submarket dynamics across San Francisco and the Bay Area. Reach out to us at Novo Real Estate to walk through a specific deal, or browse our commercial and investment listings and San Francisco multi-family properties.
