Enrollment
371
High
DISTRICT 689 · STATE 738
SCHOOL COMMUNITY·PHILADELPHIA CITY SD·NCES 421899007534
Building 21
6501 Limekiln Pike, Philadelphia, PA 19138 · (215) 400-7450 · Philadelphia County
GRADES 09–12HIGH11-CITYTITLE IREGULAR SCHOOL371 STUDENTS
F
allk12 Grade
Scored higher than 4% of Pennsylvania public high schools
- FTest scores Share of students meeting the state standard in reading, math, and other tested subjects, 2023-24 and 2024-25.
- FBeats expectations How far test scores land above or below what the share of low-income students predicts for a school in this state.
- ·Three-year trend Not available for this school, so the grade uses the other parts.
Grades compare a school only with schools in the same state, because every state gives its own test. How grades work · Top-graded Pennsylvania public high schools
Student : Teacher
20.5:1
18 FTE teachers
DISTRICT 18.7:1 · STATE 12.8:1
Free / Reduced Lunch
103%
382 students
DISTRICT 99% · STATE 75%
Community
0
0 members
Enrollment and student:teacher ratio compared against other high schools. Free/Reduced Lunch and demographics compared against all schools.
Enrollment by grade, 2024-25
| Grade | Students | Share |
|---|---|---|
| Grade 9 | 111 | 30% |
| Grade 10 | 108 | 29% |
| Grade 11 | 78 | 21% |
| Grade 12 | 74 | 20% |
Student demographics
16%Diversity index
The chance that two students picked at random belong to different racial or ethnic groups.
DISTRICT 71% · STATE 59% · US 70%
Student head counts by race/ethnicity from federal NCES enrollment data. District, state, and US figures are each group's share of all public school students in that area (US excludes territories). Very small groups may be suppressed in the source, so categories do not always sum exactly to total enrollment.
Gender split
Test scores
PSSA + Keystone 2024-25 . % Proficient or AdvancedEnglish Language Arts
24.2%
PA avg 51.1% . -0.8pp since 2023
Math
2.9%
PA avg 43.0% . +0.3pp since 2023
What this means: On the PSSA + Keystone, Pennsylvania's statewide test, about 24 of every 100 students at this school read and write at grade level and about 3 of 100 do math at grade level. Across all Pennsylvania schools, those numbers are about 51 and 43. Reading and writing scores have held steady since 2023, while math scores have held steady.
PSSA + Keystone results by year
| School year | English Language Arts | Math |
|---|---|---|
| 2024-25 | 24.2% | 2.9% |
| 2023-24 | 25.0% | 2.6% |
% Proficient or Advanced, all students and all tested grades.
Source: PSSA + Keystone. All students, all grades. See all years and grades →
BeatsExpectations
Demographically-adjusted score · methodologyTier
UNDERPERFORMING
Bottom 10% of PA schools after controlling for student poverty
Actual proficiency
10.1%
composite math + reading, all grades
Predicted
33.5%
based on PA schools with similar FRL share
Beats by
-23.4pp
below demographic expectation
What this means: About 10% of students here test proficient in math and reading, below the roughly 33% typical for Pennsylvania schools with a similar share of low-income students. BeatsExpectations compares each school with others at the same poverty level, not by raw scores, so a school lands here when its results trail those comparable schools, which is not the same as having low scores. A higher-scoring school can still fall in this tier if similar schools score higher still.
BeatsExpectations runs a per-state regression of proficiency on free/reduced-lunch share, then scores each school by residual. How this is calculated →
Where Building 21 ranks
Among high schools| Measure | This school | In Pennsylvania | In Philadelphia County |
|---|---|---|---|
| State test proficiency ranked highest first | 10.1% | #563 of 576 | #52 of 57 |
| Math proficiency ranked highest first | 2.9% | #603 of 626 no change | #63 of 67 ▼ 5 |
| Reading proficiency ranked highest first | 24.2% | #584 of 626 ▲ 4 | #50 of 67 ▲ 2 |
| Enrollment ranked largest first | 371 | #508 of 713 | #55 of 70 |
| Students per teacher ranked fewest first | 20.5:1 | #574 of 601 | #46 of 65 |
| Diversity index ranked most diverse first | 16.2% | #427 of 604 | #59 of 65 |
| Free and reduced lunch ranked highest share first | 103% | #63 of 619 | #13 of 67 |
| Enrollment change since 2017-18 ranked fastest growth first | +3.9% | #158 of 221 | #27 of 31 |
Ranked against other public high schools. Online schools are left out of every list, and test-score lists leave out schools that serve specialized populations. Each rank links to the full list. Arrows under a test-score rank show places moved since the prior test year, among schools tested both years.
4-year change
SY 2020-21 vs SY 2024-25Enrollment
371
-26 (-7%) vs 2020
Student : Teacher
20.5:1
was 19.9:1
Source: NCES Common Core of Data
Enrollment and staffing by year
| School year | Students | Teachers (FTE) | Students per teacher | Free and reduced lunch |
|---|---|---|---|---|
| 2024-25 | 371 | 18.1 | 20.5:1 | N/A |
| 2023-24 | 382 | 25.2 | 15.2:1 | 100% (382) |
| 2022-23 | 388 | 20.2 | 19.2:1 | 100% (388) |
| 2020-21 | 397 | 20 | 19.9:1 | 99% (394) |
| 2017-18 | 357 | 12.8 | 27.8:1 | 99% (355) |
| 2015-16 | 289 | 8 | 36.1:1 | 100% (289) |
Source: NCES Common Core of Data. Rows are the federal collections on file for Building 21.
Since 2017-18: students up 4% (357 to 371); teachers up 41% (12.8 to 18.1).
About Building 21
Building 21 is a public small high school in Philadelphia, Pennsylvania. Classes run from 9 through 12, and the school has 371 students. Against the 738-student average for high schools in Pennsylvania, enrollment here is 50% lower.
The 220 schools of Philadelphia City SD, including Building 21, enroll 116,230 students.
Most students at Building 21 are Black: 91% of enrollment. Enrollment also includes 5% Hispanic and 2% multiracial. The school's Black share is 52 points above the 39% share among Philadelphia County residents. By the diversity index, Building 21 comes in at 16%.
Federal records show a student-to-teacher ratio of 20.5:1 at Building 21, with 18.1 full-time-equivalent teachers. Among high schools in Pennsylvania, the typical ratio is 12.8:1.
allk12 grades Building 21 an F. The grade compares the school only with Pennsylvania public high schools, because each state gives its own test.
After accounting for student poverty, Building 21 is in the bottom 10% of Pennsylvania schools. Its average proficiency rate on state tests of 10.1% is 23.4 points below the 33.5% predicted for its lunch-eligibility share.
According to the American Community Survey, in Philadelphia County, median household income is about $61,953, the share of adults with a bachelor's degree or higher is 35%, and about 17% of people live in poverty. Building 21 is one of 309 public schools in Philadelphia County, which together enroll about 182,005 students.
Wagner Gen Louis Middle School is the public school closest to Building 21, about 0.3 miles away. Inside a five-mile radius, there are at least 8 other public schools. The average proficiency across nearby scored schools is 16.8%; Building 21's is 10.1%, ranking 7th of 9.
Building 21 is inside a principal city with a population of 250,000 or more, a location NCES labels City: Large.
Building 21 saw enrollment fall 7% between 2020-21 and 2024-25.
The Building 21 community page is open for posts about school events, clubs, and volunteer needs. Posting is open to anyone connected to the school.
Philadelphia County at a glance
View full county profilePopulation
1,579,706
Census ACS
Median income
$61,953
Household, ACS
Bachelor's+
35%
Adults 25+
Poverty rate
17%
Below federal line
Schools in county
309
182,005 students
Quick facts
Related schools
Other schools in Philadelphia City SD
- Northeast High SchoolHigh · 3,463 students
- Lincoln High SchoolHigh · 2,472 students
- Central High SchoolHigh · 2,329 students
- Northeast Community Propel AcademyElementary · 1,783 students
- Mayfair SchoolElementary · 1,763 students
- Washington George High SchoolHigh · 1,755 students
Other schools in Philadelphia
- Northeast High SchoolHigh · 3,463 students
- Philadelphia Performing Arts CSCombined · 2,572 students
- Lincoln High SchoolHigh · 2,472 students
- Central High SchoolHigh · 2,329 students
- MaST Community CS IICombined · 1,875 students
- First Philadelphia Preparatory CSCombined · 1,831 students
Nearby schools
- Wagner Gen Louis Middle School0.3 mi · 296
- Imhotep Institute CHS0.3 mi · 603
- Rowen William School0.4 mi · 296
- Prince Hall School0.4 mi · 360
- King Martin Luther High School0.5 mi · 527
- Mastery CS-Francis D. Pastorius Elementary0.6 mi · 647
Frequently asked questions
About Building 21How large is Building 21?
Building 21 enrolls approximately 371 students in grades 09-12.
What grades does Building 21 serve?
Building 21 serves grades 09-12.
How many teachers does Building 21 have?
Building 21 employs 18 FTE teachers, for a student-to-teacher ratio of 20.5:1.
How diverse is Building 21?
Building 21 reports a student body of 0% White, 5% Hispanic, 91% Black, 1% Asian, 2% Two or more.
Is Building 21 public or private?
Building 21 is a public K-12 school, overseen by Philadelphia City SD.
Data sourceSchool profile facts are sourced from the NCES. Community content is posted by allk12 members.