New York City's public school buildings hold 213,528 more seats than students, yet 337 of them are over capacity, and every one of the 32 school districts has both a crowded building and one less than 60 percent full.
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Ranked by how many students could move before the crowded building reached 100 percent or the emptier one ran out of seats. Both buildings serve exactly the same grades and have at least 300 seats. Buildings whose crowding includes a co-located charter school, and the specialized high schools, are left out of this list but remain on the map.
Source: Department of Education class size report, Table C, data as of Oct. 31, 2025, matched by school to the building that holds most of each school's students. District 75 special education schools and charter schools are not in Table C.
| Building | Name | District | Grades | Students | Target seats | Use | Classes within cap |
|---|
Capacity. All figures use the Blue Book's "target" calculation, which the School Construction Authority describes as aspirational: it assumes class sizes of 20 in kindergarten through third grade, 23 in fourth through eighth and 25 in high school, and a full set of specialty rooms. A building's use is its enrollment divided by that capacity. Building totals combine every organization in a building, including co-located charter schools, District 75 special education programs and school-based pre-K; pre-K run by outside providers is not counted.
The formula changed in 2019–20. That year's Blue Book cut the planning class size from 28 to 23 in grades 4 to 8 and from 30 to 25 in high school, so the 2013–14 to 2018–19 editions and the 2021–22 and 2025–26 editions are not strictly comparable. NYC Open Data carries only seven editions (2013–14, 2015–16 to 2018–19, 2021–22 and 2025–26); the 2014–15, 2019–20, 2022–23, 2023–24 and 2024–25 Blue Books are published as PDFs but are not in the dataset.
Grades. Each building is tagged with the grade bands its general-education schools serve (elementary, prekindergarten to fifth grade; middle, sixth to eighth; high school, ninth to 12th), using the "Grades Final" field in the Department of Education's school directory (LCGMS). A school counts toward its building's grades if it has at least 10 percent of the building's students. District 75 and District 79 programs are left out of this tag.
Distances. Buildings are placed at their own street address (geocoded by the Department of City Planning's Facilities Database, then the 2019–20 school locations file, then NYC GeoSearch). Buildings that could be placed only at a school's main site, often annexes, are drawn on the map but left out of every distance comparison. Distances are straight-line miles and ignore highways, rail yards and attendance zones. A crowded building's "near" building must not share a school with it and must be more than 0.01 mile away, which excludes campus buildings that share one address point.
Under one roof. A building counts as split when at least two schools in it, each with at least 50 students and 50 seats, sit on either side: one above 100 percent of its assigned capacity and one below 60 percent. District 75 special education programs (whose capacity uses different room ratios) and District 79 alternative programs are left out. A charter school's capacity is the target formula applied to the rooms it was assigned; charters are not bound by the class-size law and some run larger classes by design, so a charter above 100 percent is not necessarily overcrowded.
What else to keep in mind. Some crowded buildings house high schools that admit students citywide by test or audition, such as Stuyvesant, Brooklyn Tech and LaGuardia, where crowding reflects demand rather than the neighborhood. Some underused buildings are new and still filling grade by grade. And a seat on paper is not a classroom a family can use: moving students between buildings means zoning changes, an educational impact statement and a Panel for Educational Policy vote.
The first version, published earlier on Nov. 6, counted every school's classes in every building it occupied, inflating the class-size figures; reported citywide class-size totals (1,561 schools, 120,035 non-exempt classes, 22,527 exempt) that do not appear in the source, which has 1,533 schools, 140,209 non-exempt classes and 10,535 exempt; said the class-size law reaches full compliance in 2027–28, when the 2026 amendment moved that to 2029–30; placed buildings at a school's main-site coordinates rather than their own address, which put some annexes in the wrong spot; counted crowded buildings as near a half-empty one regardless of the grades either served; described a six-row 2026 snapshot that is not in the data; listed edition totals in its methodology that did not match its own data; counted 46 split buildings by including District 75 and District 79 programs; and opened its map on LaGuardia High School, which admits students citywide by audition. All are corrected here.
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