425 Market St
425 Market St is a 38-story building in Downtown San Francisco with 68% of its floor area within daylight reach of a facade. This screen estimates 749 homes and scores it 55 out of 100 for office-to-residential conversion suitability.
CA-11 · Screened 2026-10-12 · Worth a feasibility study
Where 425 Market St is
Its block in Downtown San Francisco, drawn from San Francisco's own building outlines and street centerlines.
- Already housing
- Not screened
- 425 Market St
This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.
Every floor carries 8,947 sq ft of windowless core — area that must be gutted, seismically braced and sprinklered but can never be rented as an apartment. Across 37 residential floors that is 331,040 sq ft of cost carrying no revenue.
Modeled conversion metrics for 425 Market St, 2026-10-12.
| Suitability scoreWorth a feasibility study | 55 / 100 |
|---|---|
| Storiesfrom 497 ft LiDAR (2010) height ÷ 12 ft floor-to-floor | 38 |
| Floor plateper floor, from the city footprint | 27,939 sq ft |
| Daylight efficiencyshare within 35 ft of a facade | 68% |
| Deepest interior pointviability threshold is 80 ft | 68 ft |
| Windowless coreper floor — renovated but never rentable | 8,947 sq ft |
| Estimated homesat 750 sq ft average | 749 |
| Conversion cost$405/sq ft all-in on 1,033,746 sq ft | $418.7M |
| Gap before grantshortfall against completed value | $144.5M |
| Modeled RESIDE grantat the statutory per-award cap | $10.0M |
| BuiltSan Francisco's own record of the construction year | 1973 |
| ZoningFinancial District/South Beach | C-3-O(SD) |
| Opportunity Zonenot in a 2018 designated tract | No |
The plan: window line, shape and floor rhythm
33 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.
The typical floor has 677 ft of exterior wall, and across 37 residential floors the building carries 25,035 ft of it in total, divided among the 749 homes this screen estimates.
Its plate is compact at 0.77: close to a square or a circle, the most efficient envelope an office can have and the least generous one for apartments: little perimeter to divide among homes. How window line and plate shape are measured.
At the model’s 750 sq ft average, the plan works out at about 20.2 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.
Why 425 Market St scores 55 out of 100
Daylight efficiency 56, Interior depth 30, Scale 100, Finance 46 — each out of 100, then weighted.
Score components for 425 Market St. Points are the subscore times its weight.
| Component | Subscore | Weight | Points |
|---|---|---|---|
| Daylight efficiency68% of the floor area within 35 ft of a facade, scored from 40% up to 90% | 56 | 45% | 25.2 |
| Interior depthdeepest interior point 68 ft from a facade, scored from 80 ft down to 40 ft | 30 | 25% | 7.5 |
| Scale749 estimated homes, scored from 0 up to 150 | 100 | 15% | 15.0 |
| Financeremaining gap is 32% of conversion cost, scored from 60% down to 0% | 46 | 15% | 7.0 |
Most of what it earns comes from daylight efficiency, and what holds it back most is interior depth, at 30 out of 100: deepest interior point 68 ft from a facade, scored from 80 ft down to 40 ft.
Built in 1973
San Francisco records this building as going up in 1973, which puts it in the late-modern stock.
As a rule, typically the hardest to convert: the deepest plates of any era, large central cores, and floor-to-floor heights tight enough that running residential drainage under a ceiling can be the thing that ends a project. That is the era’s general tendency rather than a finding about this building — the model reads an outline and a height, and can see nothing inside — but it is the first thing an architect would want to know, and it colours how much confidence the 68% daylight figure above deserves.
What the conversion would cost
$405 per square foot all-in across 1,033,746 sq ft of converted floor, or $418.7M in total — about $559K for each of the 749 homes.
All-in cost per square foot for 425 Market St: base cost plus the code work a change of use triggers.
| Base conversion cost | $260/sq ft |
|---|---|
| Seismic retrofit (change of use) | $45/sq ft |
| Plumbing risers to every unit | $40/sq ft |
| Operable windows and glazing | $30/sq ft |
| Additional egress stair | $18/sq ft |
| Fire sprinklers (NFPA 13R) | $12/sq ft |
| All-in | $405/sq ft |
That cost is charged across every converted square foot, including the 331,040 sq ft of windowless core, which has to be gutted, seismically braced and sprinklered like the rest of the building and then earns nothing. Against it the model sets a completed value of $366K a home, which for 749 homes is $274.1M.
What would have to be true
A $144.5M gap before any grant, $134.5M after the modeled one. The smallest single change that would close it: average unit size 33% down.
The shortfall before any grant is $144.5M. Closing it from the value side means each of the 749 homes finishing at $559K rather than the $366K the model assumes — 53% more. Closing it from the cost side means getting all-in cost down from $405 to $265 per square foot.
A modeled RESIDE grant of $10.0M moves that threshold to $546K a home. That is still above the $366K assumed, leaving $134.5M uncovered, which is why the grant does not unlock this one.
Nor do all four levers have to move. For 425 Market St, one alone would close the gap at:
Single-assumption flip points for 425 Market St, each holding the other three at their defaults.
| Average unit sizethe binding constraint — the least this building would need | 33% downto 503 sq ft |
|---|---|
| Completed value per home | 49% upto $546K |
| Conversion cost per square foot | 50% downto $130/sq ft |
All four are sliders in the survey, where 425 Market St re-scores against your own numbers.
How it compares in Downtown San Francisco
425 Market St ranks 185th of the 205 buildings screened here, against a median score of 87.
Its floor plate is better lit than 8% of them, and shallower than 15% of them at its deepest interior point. On size it is the 5th largest by estimated homes. The full survey of all 205 buildings ranks and maps every one of them, and the list by address links each to its own page.
Within Financial District/South Beach and the C-3-O(SD) zone
152nd of 165 in Financial District/South Beach, 57th of 66 zoned C-3-O(SD) — the comparison that shares its rules, rents and streets.
San Francisco places 165 of the screened buildings in Financial District/South Beach. 425 Market St ranks 152nd of them against a median score of 88. 121 score 70 or more, their median deepest interior point is 47 ft from a facade against this building’s 68 ft, and together they would hold an estimated 40,456 homes. The group’s top scorer is 870 Market St, at 100.
66 of the screened buildings are zoned C-3-O(SD). 425 Market St ranks 57th of them against a median score of 72. 37 score 70 or more, their median deepest interior point is 59 ft from a facade against this building’s 68 ft, and together they would hold an estimated 18,546 homes. The group’s top scorer is 140 New Montgomery St, at 100.
Its nearest match in size: 525 Market St
The screened building closest to 425 Market St in converted floor area is 525 Market St: 1,067,419 sq ft over 38 stories, against 1,033,746 sq ft over 38 here.
425 Market St scores 55 to its 46, and with the size held roughly equal most of that lead comes from interior depth: 30 out of 100 here, 6 there (deepest interior point 77 ft from a facade, scored from 80 ft down to 40 ft). On the money they sit in the same place: each falls short even with the modeled grant. The two stand about 400 ft apart.
Would it qualify for a RESIDE Act grant?
The model awards 425 Market St $10.0M, on the assumption it qualifies. Whether it does, no published dataset can say.
That figure assumes the building meets the Act’s vacant-and-abandoned test, which turns on code-enforcement and receivership records no city publishes.
It does not sit in a 2018 designated Opportunity Zone, so it would not draw that Section 201 priority.
Other buildings screened near 425 Market St
The 4 closest the screen also covers, from 180 ft away. They are the colored outlines on the plan at the top of this page.
- 21 1st St23 stories · 83% daylit · 291 estimated homes · scores 81/100 (Strong candidate)about 180 ft away
- 45 Fremont St34 stories · 76% daylit · 511 estimated homes · scores 69/100 (Worth a feasibility study)about 290 ft away
- 40 Battery St38 stories · 79% daylit · 724 estimated homes · scores 68/100 (Worth a feasibility study)about 300 ft away
- 333 Market St33 stories · 76% daylit · 508 estimated homes · scores 68/100 (Worth a feasibility study)about 350 ft away
A screen, not a feasibility study, from outlines and heights rather than plans: the method and how to correct a figure. If you know this building’s interior, you know what this model cannot see.