Building 21
🇺🇸 Official data · 2025Philadelphia, Pennsylvania 19138 · Philadelphia City SD
#611 of 618 high schools in Pennsylvania
#16656 of 16,910 nationally
About Building 21
Building 21 is a public high located in Philadelphia, in the Philadelphia City SD school district of Pennsylvania, United States. It caters for Grades 9–12. In 2025 it enrolled 371 students. Traditional public schools run by a school district; free to attend.
Its Success Index (US) is 9.2 out of 100, placing it in the lower 50% of high schools in United States and 611th of 618 ranked high schools in Pennsylvania. Its strongest component is reading proficiency (18th percentile), and its weakest is community advantage (fewer free/reduced-price lunch) (1th percentile).
Other published figures: enrollment 371.
There are 292 schools in Philadelphia; Building 21 ranks 265th of 275 scored schools there.
Success Index (US) breakdown
Each component is a percentile against high schools across United States.
- Math proficiency (30%)7.5%
- Reading proficiency (30%)32%
- Community advantage (fewer free/reduced-price lunch) (25%)103%
- Students per teacher (15%)20.6
The Success Index (US) summarises published data about a school community. It is not a measure of teaching quality. Read the methodology.
Published measures
All figures published for Building 21 by the official sources.
- Enrollment
- 371
- Students enrolled in the latest NCES directory year.
- Free/reduced-price lunch
- 103%
- Share of students eligible for free or reduced-price lunch.
- Students per teacher
- 20.6
- Enrollment divided by FTE teachers; not class size.
- Reading proficiency
- 32%
- Share of tested students proficient or above (all students, all grades).
- Math proficiency
- 7.5%
- Share of tested students proficient or above (all students, all grades).
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Schools near Building 21
Closest schools by straight-line distance, with their Success Index (US).
Wagner Gen Louis MS
Philadelphia · Public middle · Grades 6–8
296 students · 460 m away
Imhotep Institute CHS
Philadelphia · Charter high · Grades 9–12
603 students · 522 m away
Rowen William Sch
Philadelphia · Public elementary · Grades K–5
296 students · 669 m away
Prince Hall Sch
Philadelphia · Public elementary · Grades PK–5
360 students · 701 m away
King Martin Luther HS
Philadelphia · Public high · Grades 9–12
527 students · 822 m away
Mastery CS-Francis D. Pastorius Elementary
Philadelphia · Charter elementary · Grades K–8
647 students · 986 m away
West Oak Lane CS
Philadelphia · Charter elementary · Grades K–8
955 students · 1.1 km away
Parkway Northwest
Philadelphia · Public high · Grades 9–12
238 students · 1.1 km away
Pennell Joseph Sch
Philadelphia · Public elementary · Grades PK–5
301 students · 1.1 km away
Ellwood Sch
Philadelphia · Public elementary · Grades PK–5
292 students · 1.2 km away
Similar schools
Public high schools in Pennsylvania with a comparable Enrollment.
Penns Manor Area JSHS
Clymer · Public high · Grades 6–12
371 students
Canton JSHS
Canton · Public high · Grades 7–12
372 students
Juniata Valley JSHS
Alexandria · Public high · Grades 6–12
374 students
Moshannon Valley JSHS
Houtzdale · Public high · Grades 7–12
374 students
Freedom Area SHS
Freedom · Public high · Grades 9–12
366 students
Rocky Grove JSHS
Franklin · Public high · Grades 7–12
366 students
Frequently asked questions
Is Building 21 a good school?
Building 21 has a Success Index (US) of 9.2 out of 100 (Lower 50% of high schools in United States) and ranks #611 of 618 in Pennsylvania. The index summarises published data about the school community and, where available, attainment; it does not measure teaching quality, so visit the school and ask about support at your child's level.
Where does Building 21 rank in Pennsylvania?
Building 21 ranks #611 of 618 high schools in Pennsylvania and #16656 of 16,910 nationally on the Success Index (US) (2025 data).
How many students attend Building 21?
Building 21 had 371 students in 2025.
Is Building 21 a elementary school or a high school?
Building 21 is classified as a high covering Grades 9–12. It is a public school.
What other schools are near Building 21?
There are 10 schools within 15 km of Building 21; they are listed on this page with their Success Index (US) and distance, and can be compared side by side.