How to Value an Apartment Building in San Francisco

If you own a multi-unit building in San Francisco, or you're trying to buy one, a generic national cap rate calculator won't get you far. It doesn't account for rent control, doesn't know your building might need a soft story retrofit, and has no idea a building in the Marina trades differently than one in the Bayview.

This guide covers a general guide on how San Francisco multi-unit buildings get valued, for owners weighing a sale, hold, or refinance and for investors underwriting a purchase: the core formulas, the San Francisco factors that shift price, and real local transactions so you can see the math applied to buildings that closed.

Allison Chapleau has worked exclusively in San Francisco multi-unit and commercial real estate since 2002, with over $1 billion in career transaction volume across 300+ multi-unit, mixed-use,  commercial, and apartment buildings sold. If you'd rather skip straight to real numbers, you can request a San Francisco property valuation directly.

What "Value" Means for a San Francisco Multi-Unit Building

Appraisers lean on three approaches to value: the cost approach (rebuild cost), the sales comparison approach (what similar properties sold for), and the income approach (what cash flow says it's worth). For San Francisco apartment buildings, the cost approach rarely matters. The income and sales comparison approaches do the real work.

Which one carries more weight depends on building size. A 2-4 unit building in San Francisco is usually valued like a single-family home: pull recent comps and adjust for condition, unit count, and location. Owner-users compete alongside investors, and lenders often use residential-style financing, so comps carry heavy weight.

A 5+ unit building shifts the calculation toward income. These properties trade in the commercial financing world, where NOI relative to price drives the conversation and comps mainly sanity-check that number. If you own a smaller building, this breakdown of owner-occupied multi-unit properties in San Francisco covers how that segment behaves differently.

The Core Formulas: NOI, Cap Rate, and GRM for San Francisco Buildings

Three numbers drive almost every San Francisco multi-unit conversation.

Net operating income (NOI) is annual income after operating expenses, before debt payments: gross rental income minus property tax, insurance, repairs, and management. Mortgage payments and capital improvements aren't included.

Cap rate measures NOI against property value. Per JPMorgan Chase's overview of how cap rates work, cap rate equals NOI divided by property value or price. JPMorgan's example: a property worth $14 million generating $600,000 of NOI has a cap rate of 4.3%. Flip it around and divide a building's NOI by a market cap rate to estimate value.

Gross rent multiplier (GRM) is quicker and rougher. Per JPMorgan Chase's breakdown of the gross rent multiplier formula, GRM is price divided by annual gross rent, before expenses. A lower GRM generally signals a better estimated return.

Cap Rate vs GRM: When to Use Which in San Francisco

GRM is fast: two numbers, done, a useful first filter across San Francisco listings. But it ignores operating expenses, which vary widely between a well-maintained building and one carrying deferred maintenance or a looming soft story retrofit.

Cap rate takes more work since it needs real expense figures, but it's more precise since it's built on NOI. The JPMorgan report above put the San Francisco multifamily cap rate at 4.50% as of the fourth quarter of 2025, unchanged from a year earlier, one dated data point, not a claim about today's market. Cap rates move with interest rates, class, condition, and neighborhood, so treat 4.50% as a reference point, not a guarantee. Our San Francisco multi-unit market reports track how these figures shift.

Buyers typically use both together: GRM narrows the list, cap rate does the underwriting.

A Hypothetical San Francisco Valuation Walkthrough

Before going further: what follows is a hypothetical, illustrative example built on round numbers. It is not a real transaction, and none of the figures below describe an actual San Francisco property.

Say you're looking at a 6-unit building. Each unit rents for $2,500 a month, giving gross annual rent of $180,000. Apply an illustrative 35% expense ratio, and expenses come to $63,000 a year, leaving NOI at $117,000.

Apply an illustrative 5% cap rate: $117,000 divided by 0.05 equals $2,340,000, your estimated value using the income approach. The GRM on the same numbers, $2,340,000 divided by $180,000, equals 13.

Now raise each unit's rent by $200 a month. New rent per unit is $2,700, so six units brings gross annual rent to $194,400. At the same expense ratio, NOI rises to $126,360, and at the same cap rate, value climbs to $2,527,200, roughly $187,200 higher from that rent bump alone. The GRM stays at 13, since it only reflects price against gross rent when cap rate and expense ratio hold steady, a sign that GRM alone won't capture everything a rent increase does to value.

Again, this whole example is hypothetical. Real San Francisco buildings carry rent-controlled units, uneven expense histories, and cap rates that shift by neighborhood and condition, so an actual valuation needs real numbers, not round figures.

San Francisco-Specific Factors That Move the Price

Rent Control's Effect on In-Place Income in San Francisco

San Francisco's Rent Ordinance generally applies to buildings with two or more units built on or before June 13, 1979. Covered units can see only one rent increase every 12 months, up to the Annual General Adjustment set by the Rent Board. Per sf.gov, the current allowable rent increase is 1.6%, effective March 1, 2026 through February 28, 2027.

That limit matters for valuation. A tenant who's stayed a decade or more may pay well below what the unit would fetch today, suppressing current NOI relative to the building's real income potential. Sophisticated buyers underwrite both in-place NOI and market, or pro forma, NOI based on what units could fetch after turnover. A building with heavily below-market rents often carries a higher cap rate at asking price, since the buyer is pricing in the time it takes to reach market rents.

The Mandatory Soft Story Retrofit Program and San Francisco Underwriting

San Francisco's Mandatory Soft Story Retrofit Program covers wood-frame buildings with five or more residential units, two or more stories over a soft or weak story condition, built before January 1, 1978, and not already retrofitted. If your building fits that, a lender and insurer will want to know.

The city's CAPSS study, referenced on the Department of Building Inspection's soft story program page, estimated retrofit costs between $60,000 and $130,000 per building. That range shows up in negotiations often: buyers price an unfinished retrofit into their offer, or negotiate a credit at closing.

Neighborhood and District Price Variation Across San Francisco

Location has always shaped San Francisco real estate. Proximity to transit, employment centers, and retail districts tends to support stronger demand, while less central pockets of the city see more variability in buyer interest and financing terms. Since these differences shift by district and over time, our San Francisco multifamily market insights page is the better place for current, neighborhood-level detail.

The Comparable Sales Approach: Reading Recent San Francisco Deals

Real transactions tell you more than any formula alone. 691 Post Street, a 36-unit mixed-use building in Downtown San Francisco, sold for $9,000,000 at a 4.32% cap rate and a 12.73 gross rent multiplier. Working backward through the formulas above, that implies an NOI of roughly $388,800 a year and gross annual rent of roughly $707,000. The building accepted an offer within two weeks.

Larger and smaller buildings tell different stories. 625 Scott Street, a 42-unit building across from Alamo Square, sold for $18,050,000 in 2022, San Francisco's largest multifamily sale that year, drawing four offers and closing non-contingent, a deal The Real Deal covered independently. On the smaller end, 335 2nd Avenue, a 10-unit building in the Richmond District, sold for $3,670,000, $370,000 over asking, with six offers, all cash, and a 15-day close.

These three deals show how differently size and positioning play out within the same market. Pricing, financing pools, and timelines all varied by size and location. For more, see our notable San Francisco multi-unit building sales and recently sold San Francisco apartment buildings.

Common Valuation Mistakes San Francisco Buyers and Sellers Make

A few mistakes come up again and again in San Francisco multi-unit deals:

• Relying only on in-place NOI. Long-tenured, rent-controlled tenants can make in-place NOI understate a building's real capability after turnover.
• Assuming a low cap rate means a bad deal. A lower cap rate often reflects a stronger location or better condition, not a bad price. Read it alongside comps in the same district.
• Treating GRM and cap rate as interchangeable. GRM ignores expenses. Two buildings with identical GRMs can have very different NOI once costs are factored in.
• Underestimating tenant turnover effects. Turnover can drive the biggest NOI gains, but it can take years, and buyers need to underwrite that timeline realistically.
• Forgetting soft story costs. An unaddressed retrofit obligation isn't a minor line item. At $60,000 to $130,000, it can change what a buyer will pay.

How to Get an Accurate Value for Your San Francisco Building

Start with recent comparable sales similar in size, condition, and location to yours. Then run the income approach using your actual rent roll and operating expenses, not estimates, and cross-check the two. A gap between them usually points to below-market rents, deferred maintenance, or an unusual expense ratio.

A professional valuation from an agent like Allison Chapleau who works exclusively in San Francisco multi-unit property, rather than a generalist, will catch what a generic estimate misses: which comps are truly comparable, how a soft story obligation should be priced, and what your in-place versus market rent gap is worth. As the top multi-unit realtor in San Francisco, Allison Chapleau has priced and sold hundreds of these buildings across every district in the city.

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Frequently Asked Questions About Valuing a San Francisco Apartment Building

What is a good cap rate for an apartment building in San Francisco?There's no single "good" cap rate for every San Francisco building. As a dated reference point, JPMorgan Chase put the San Francisco multifamily cap rate at 4.50% as of the fourth quarter of 2025, unchanged from a year earlier. Cap rates vary by class, condition, and district, so compare against real San Francisco comps.

What is GRM in real estate and how do I calculate it for my San Francisco building?Gross rent multiplier is price divided by annual gross rent, before expenses. For a San Francisco building, divide the sale price or estimated value by the rent it collects in a year. It's a fast filter, but it won't account for actual operating costs.

How does rent control affect the value of a San Francisco apartment building?San Francisco's Rent Ordinance generally covers buildings with two or more units built on or before June 13, 1979, and caps annual increases, currently 1.6% through February 2027. Long-tenured tenants often pay well below market rent, suppressing in-place NOI, so San Francisco buyers underwrite both in-place and market rent scenarios.

Does the Mandatory Soft Story Retrofit Program affect what my San Francisco building is worth?Yes, if it's a wood-frame building with five or more units, two or more stories over a soft story condition, built before January 1, 1978, and not yet retrofitted. San Francisco's CAPSS study estimated retrofit costs between $60,000 and $130,000, a range buyers factor into their offer or a closing credit.

What's the difference between valuing a 2-4 unit building and a 5+ unit building in San Francisco?A 2-4 unit San Francisco building is valued like a home, using comps and appraisal-style adjustments, since owner-users compete alongside investors. A 5+ unit San Francisco building leans on the income approach, since these deals trade primarily on NOI and cap rate.

How do I find comparable sales for my San Francisco apartment building?Look for recently sold San Francisco buildings similar in unit count, condition, and neighborhood, and compare price per unit, price per square foot, and cap rate, not just sale price. An agent with direct transaction history, like Allison Chapleau's notable San Francisco multi-unit building sales, can pull truly comparable deals.

Should I get a professional appraisal before selling my San Francisco multi-unit building?It's a reasonable step, especially for 5+ unit San Francisco buildings where NOI, expenses, and rent-control status need documentation. Many owners pair a formal appraisal with a market-based valuation from an agent who actively sells San Francisco multi-unit buildings.

How much does location within San Francisco affect an apartment building's value?Quite a bit. Proximity to transit, employment centers, and retail corridors supports stronger demand, while less central San Francisco neighborhoods see more variability in buyer interest and financing terms. District rent potential and turnover speed differ block by block.

What happens to my building's value if I inherit it through probate in San Francisco?Inherited San Francisco multi-unit buildings often carry below-market rents if tenants have stayed for years, widening the in-place versus market NOI gap. A probate sale still needs a defensible valuation, using comps and income data, before the building is listed or transferred.

How often do cap rates and GRMs change in the San Francisco multifamily market?Both move with interest rates, buyer demand, and economic conditions. The 4.50% San Francisco multifamily cap rate held steady between the fourth quarter of 2024 and 2025, but that stability isn't guaranteed going forward, and individual building rates vary by condition, class, and district.

If you're weighing whether to sell, hold, or refinance a San Francisco multi-unit building, or underwriting a purchase, request a San Francisco property valuation from Allison Chapleau's team, or read more about Allison Chapleau, San Francisco multi-unit broker and her track record across 300+ San Francisco apartment, mixed-use, and commercial buildings.

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