1601 Market St

1601 Market St is a 36-story building in Center City Philadelphia with 74% of its floor area within daylight reach of a facade. This screen estimates 702 homes and scores it 61 out of 100 for office-to-residential conversion suitability.

PA-2 & PA-3 · Screened 2026-09-15 · Worth a feasibility study

Build a conversion planCheck its numbers, lay out its homes and get a two-page PDF. Free.

Also addressed as 1603 Market St, 1605 Market St, 1607 Market St, 1609 Market St, 1611 Market St, 1613 Market St, 1615 Market St, 1617 Market St, 1619 Market St, 1621 Market St and 1623 Market St: Philadelphia’s address records place all 12 on this one footprint.

Where 1601 Market St is

Its block in Center City Philadelphia, drawn from Philadelphia's own building outlines and street centerlines.

1628 John F Kennedy Blvd: scores 88 out of 1001500 John F Kennedy Blvd: scores 69 out of 1001625 Market St: scores 67 out of 1001600 John F Kennedy Blvd: scores 61 out of 1001601 John F Kennedy Blvd: scores 55 out of 1001600 Market St: scores 55 out of 1001701 Market St: scores 51 out of 10022 S 17th St: scores 45 out of 1001650 Market St: scores 35 out of 1001700 Market St: scores 31 out of 1001500 Market St: scores 21 out of 100886761555135312161MARKET STN 16TH STN 17TH STS 17TH STS 16TH STN100 ftCenter City Philadelphia
Suitability score
0–29
30–49
50–69
70–100
  • Already housing
  • Not screened
  • 1601 Market St
1601 Market St and the 1,000 ft of Center City Philadelphia around it. The streets are drawn at the width of the right-of-way they run down, sidewalks included, and named, and every building on these blocks is drawn. What is left open and stippled is neither: a surface lot, a plaza or a vacant parcel. The screened buildings are colored by the ramp above, the same one the district map uses, carry their score, and each is a link to its own page. Each casts a shadow as long as its measured height lets it, so towers stand out from the low buildings around them; the unscreened buildings have no measured height and cast none. 1601 Market St is outlined in its own score color at the outline it covers at ground level. Its windowless core is hatched. The inset places it among every building the screen covers.
58 ftAA100 ftDaylit 74%Core 6,563 sq ft
Floor plan: 74% of each floor sits within daylight reach of a facade. The shading is daylight, darkest at the windows and gone 35 ft in. The hatched area is windowless core: 6,563 sq ft per floor that must be renovated but can never be rented as an apartment. The dimension marks the deepest interior point, 58 ft from the nearest window. A–A is where the section beside it is cut.
Windowless core36 floors50 ft
Section A–A: cut across the depth of the plate, through the middle of the core. Daylight reaches 35 ft in from every facade, fading as it goes, and the hatched stripe left between the lit edges is floor that gets converted and can never be rented: 6,563 sq ft on the floor the screen scores, and 229,722 sq ft over 35 residential floors. The shaded ground floor is converted like the rest and counted as no homes.

This building does not pencil at default assumptions, even with a modeled RESIDE Act grant.

Every floor carries 6,563 sq ft of windowless core — area that must be gutted, re-plumbed and sprinklered but can never be rented as an apartment. Across 35 residential floors that is 229,722 sq ft of cost carrying no revenue.

Modeled conversion metrics for 1601 Market St, 2026-09-15.

Suitability scoreWorth a feasibility study61 / 100
Storiesfrom 481 ft LiDAR height ÷ 12 ft floor-to-floor36
Floor plateper floor, from the city footprint25,371 sq ft
Daylight efficiencyshare within 35 ft of a facade74%
Deepest interior pointviability threshold is 80 ft58 ft
Windowless coreper floor — renovated but never rentable6,563 sq ft
Estimated homesat 750 sq ft average702
Conversion cost$360/sq ft all-in on 887,997 sq ft$319.7M
Gap before grantshortfall against completed value$181.6M
Modeled RESIDE grantat the statutory per-award cap$10.0M
BuiltPhiladelphia's own record of the construction year1970
ZoningCenter City PhiladelphiaCMX5
Opportunity Zonenot in a 2018 designated tractNo

The plan: window line, shape and floor rhythm

34 ft of exterior wall for each home the screen estimates — enough for two- and three-bedroom homes across the plan.

The typical floor has 683 ft of exterior wall, and across 35 residential floors the building carries 23,922 ft of it in total, divided among the 702 homes this screen estimates.

Its plate is moderately compact at 0.68: a squarish plan, with enough perimeter for a conventional double-loaded corridor. How window line and plate shape are measured.

At the model’s 750 sq ft average, the plan works out at about 20.1 homes per floor, repeated on every residential floor, since this building's outline does not change as it rises.

Why 1601 Market St scores 61 out of 100

Daylight efficiency 68, Interior depth 54, Scale 100, Finance 11 — each out of 100, then weighted.

Score components for 1601 Market St. Points are the subscore times its weight.

ComponentSubscoreWeightPoints
Daylight efficiency74% of the floor area within 35 ft of a facade, scored from 40% up to 90%6845%30.7
Interior depthdeepest interior point 58 ft from a facade, scored from 80 ft down to 40 ft5425%13.5
Scale702 estimated homes, scored from 0 up to 15010015%15.0
Financeremaining gap is 54% of conversion cost, scored from 60% down to 0%1115%1.6

Most of what it earns comes from daylight efficiency, and what holds it back most is finance, at 11 out of 100: remaining gap is 54% of conversion cost, scored from 60% down to 0%.

Built in 1970

Philadelphia records this building as going up in 1970, 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 74% daylight figure above deserves.

What the conversion would cost

$360 per square foot all-in across 887,997 sq ft of converted floor, or $319.7M in total — about $455K for each of the 702 homes.

All-in cost per square foot for 1601 Market St: base cost plus the code work a change of use triggers.

Base conversion cost$260/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$360/sq ft

That cost is charged across every converted square foot, including the 229,722 sq ft of windowless core, which has to be gutted, re-plumbed and sprinklered like the rest of the building and then earns nothing. Against it the model sets a completed value of $197K a home, which for 702 homes is $138.1M.

What would have to be true

A $181.6M gap before any grant, $171.6M after the modeled one. The smallest single change that would close it: average unit size 55% down.

The shortfall before any grant is $181.6M. Closing it from the value side means each of the 702 homes finishing at $455K rather than the $197K the model assumes — 132% more. Closing it from the cost side means getting all-in cost down from $360 to $155 per square foot.

A modeled RESIDE grant of $10.0M moves that threshold to $441K a home. That is still above the $197K assumed, leaving $171.6M uncovered, which is why the grant does not unlock this one.

Nor do all four levers have to move. For 1601 Market St, one alone would close the gap at:

Single-assumption flip points for 1601 Market St, each holding the other three at their defaults.

Average unit sizethe binding constraint — the least this building would need55% downto 334 sq ft
Conversion cost per square foot74% downto $67/sq ft
Completed value per home124% upto $441K

All four are sliders in the survey, where 1601 Market St re-scores against your own numbers.

How it compares in Center City Philadelphia

1601 Market St ranks 58th of the 103 buildings screened here, against a median score of 67.

Its floor plate is better lit than 41% of them, and shallower than 48% of them at its deepest interior point. On size it is the 15th largest by estimated homes. The full survey of all 103 buildings ranks and maps every one of them, and the list by address links each to its own page.

Within the CMX5 zone

36th of 65 zoned CMX5 — the comparison that shares its rules, rents and streets.

65 of the screened buildings are zoned CMX5. 1601 Market St ranks 36th of them against a median score of 67. 28 score 70 or more, their median deepest interior point is 58 ft from a facade against this building’s 58 ft, and together they would hold an estimated 30,650 homes. The group’s top scorer is 112 N Broad St, at 93.

Its nearest match in size: 1600 Market St

The screened building closest to 1601 Market St in converted floor area is 1600 Market St: 881,431 sq ft over 39 stories, against 887,997 sq ft over 36 here.

1601 Market St scores 61 to its 55, and with the size held roughly equal most of that lead comes from interior depth: 54 out of 100 here, 27 there (deepest interior point 69 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 200 ft apart.

Would it qualify for a RESIDE Act grant?

The model awards 1601 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 1601 Market St

The 4 closest the screen also covers, from 170 ft away. They are the colored outlines on the plan at the top of this page.

  • 1600 John F Kennedy Blvd
    20 stories · 75% daylit · 414 estimated homes · scores 61/100 (Worth a feasibility study)
    about 170 ft away
  • 1625 Market St
    19 stories · 81% daylit · 270 estimated homes · scores 67/100 (Worth a feasibility study)
    about 220 ft away
  • 1600 Market St
    39 stories · 75% daylit · 702 estimated homes · scores 55/100 (Worth a feasibility study)
    about 220 ft away
  • 1628 John F Kennedy Blvd
    23 stories · 90% daylit · 246 estimated homes · scores 88/100 (Strong candidate)
    about 280 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.