Enrollment
371
Pennsylvania · 2024-25 NCES data
High school (grades 9-12) · Philadelphia, PA
Building 21
Federal NCES profile for Building 21, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 34/100.
2024-25 NCES dataHigh school (grades 9-12)NCES 421899007534
👥 S:T ratio 26
📚 AP courses 10
🌟 Gifted program 70
🎓 Counselors 63
📋 Attendance 0
Scored 0–100 from federal NCES and CRDC indicators, resource allocation, not test scores. Full methodology →
The verdict
Building 21 earns 34/100 on the Resource Investment Index, with class sizes larger than 96% of Pennsylvania schools.
- #28 of 57
- high schools in Philadelphia · Resource Index
- 34
- Resource Index · Typical
- 18.6:1
- large classes for Pennsylvania
- 100.0%
- free-lunch eligible
Building 21 has class sizes larger than 96% of Pennsylvania schools. Computed live against every Pennsylvania school reporting to NCES.
By Resource Investment Index, Building 21 ranks #28 of 57 high schools in Philadelphia, PA.
School address
District: Philadelphia City Sd · Pennsylvania
NCES ID 421899007534 Verify on NCES CCD record →
Teachers (FTE)
20.0
Federal CCD staff survey
Students per teacher
18.6:1
vs 13.6:1 Pennsylvania avg
+37% vs state
Free-lunch eligible
100.0%
vs 58.1% Pennsylvania avg
+72% vs state
Student-teacher ratio in context
How Building 21 compares with Pennsylvania and U.S. medians
What stands out at Building 21
Building 21 is a high-poverty, mid-sized high school in Philadelphia, Pennsylvania, enrolling 371 students.
Class loads run heavy: 18.6:1 is larger than about 96% of Pennsylvania schools and 37% above the 13.6:1 state mean, so each teacher carries more students than is typical.
Economic need runs somewhat above the state's typical profile, with 100.0% of students eligible for free meals.
Enrollment of 371 puts it in the smaller third of Pennsylvania schools by headcount.
Its Resource Investment Index lands in the lower third of 2,889 scored Pennsylvania schools.
Against 481 statewide peers matched on enrollment and economic need, it ranks mid-pack at #247.
Its student body is predominantly African American (91% of enrollment) (diversity index 16/100).
No Advanced Placement courses are reported for this campus in the federal data.
Counselor coverage is strong, about 186 students per counselor, inside the American School Counselor Association's recommended 250:1.
Chronic absenteeism is elevated: 43.1% of students missed 10% or more of school days (2021-22 Civil Rights Data Collection).
Its district draws 23.3% of revenue from federal sources, an above-typical federal share that tends to track a higher-need student population.
Among Philadelphia's high schools, it stands alongside Northeast Hs (3,463 students): Building 21 is smaller than that campus by headcount and runs leaner classes (18.6:1 vs 18.9:1).
Philadelphia City Sd also operates Northeast Hs (3,463 students) and Lincoln Hs (2,472 students) alongside Building 21.
Sourced from NCES CCD, CRDC, and F-33 (federal records, not a quality verdict). How we source and compute this.
Source: National Center for Education Statistics Common Core of Data + CRDC + F-33 · 2024-25
How Building 21 compares
Building 21 on the metrics families compare, against Pennsylvania and U.S. means.
| Metric | This school | vs Pennsylvania | Pennsylvania avg | U.S. avg |
|---|---|---|---|---|
| Students per teacher | 18.6:1 | ▲ 37% | 13.6:1 | 15.7:1 |
| Free-lunch eligible | 100.0% | ▲ 72% | 58.1% | 51.7% |
| Enrollment | 371 | top 66% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
18.6:1
Leaner classes than 22% of US schools, heavier class loads than most.
371
Bigger than 43% of US schools by enrollment, mid-sized for the country.
Equity indicators (what these measure)
Economic need
100.0%
free-lunch eligible
- 72% above the Pennsylvania average of 58.1%
Above the 40% Title I schoolwide threshold; federal funds support the whole school, not individual students.
Staffing depth
18.6:1
students per teacher
- 37% above state mean
Top 96% in Pennsylvania - lower ratio than 4% of state schools
Between 16:1 and 20:1, squarely in the typical U.S. public-school staffing range.
Engagement
43.1%
chronically absent (missed 10%+ of school days)
At or above 20%, the commonly used threshold for "high" chronic absenteeism, signaling significant barriers to regular attendance.
Funding equity
$17,892
per pupil, district-wide
- below Pennsylvania avg of $17,970
Somewhat above the U.S. public-school average, reflecting higher local or state investment per enrolled student.
Support staff
Counselors2.0 FTE
Per 186 students, the combined health-and-guidance staffing load for this school.
Discipline context
0
in-school suspensions + 23 out-of-school
Suspension rate: 0.0 per 100 students. Combined in-school and out-of-school rate: 6.2 per 100 students. Reported via the Civil Rights Data Collection.
Overview
- Common Core of Data (June 2026): enrollment, staffing, and the student-teacher ratio above.
- Civil Rights Data Collection: discipline counts and program access (AP, gifted, special education).
- F-33 School District Finance Survey: the district-wide per-pupil spending figures below.
Three separate federal collections, each on its own reporting cadence - which is why this school's numbers line up on a consistent basis against every other school and state on this site, rather than mixing figures pulled from different survey years.
Student demographics
African American 91.4%
Hispanic or Latino 5.4%
Two or More 2.2%
Asian 0.8%
White 0.3%
Largest group: African American at 91.4% of enrollment.
Student-body diversity index 16.1/100
Simpson diversity index - at 16.1, Building 21 is less mixed than the Pennsylvania school average of 37.3.
Programs
AP program Not offered
Gifted & talented Yes
Funding & spending
District-wide per-pupil expenditure for Philadelphia City Sd, which includes Building 21.
$17,892
Per student
0%
vs Pennsylvania
Avg $17,970
+8%
vs U.S.
Avg $16,593
Revenue mix
Local 37.0%
State 39.7%
Federal 23.3%
Source: NCES F-33 School District Finance Survey District-level finance · FY 2021-22 Per-pupil expenditure reflects the district-wide average. Individual school budgets are not reported at the federal level.
How Building 21 Compares to District-Mates
| School | Enrollment | Economic Profile | Student-Teacher Ratio |
|---|---|---|---|
| Northeast Hs | Larger | Similar economic need | Similar S:T ratio |
| Lincoln Hs | Larger | Similar economic need | Lower S:T ratio |
| Central Hs | Larger | Similar economic need | Higher S:T ratio |
| Northeast Community Propel Academy | Larger | Similar economic need | Higher S:T ratio |
| Mayfair Sch | Larger | Similar economic need | Higher S:T ratio |
Comparisons are relative to Building 21's own figures; each column derives from NCES Common Core of Data.
Other Schools in This District
- Enrollment
- 3,463
- Students per teacher
- 18.9:1
- Resource Index
- 31/100
- Enrollment
- 2,472
- Students per teacher
- 17:1
- Resource Index
- 34/100
- Enrollment
- 2,329
- Students per teacher
- 20.1:1
- Resource Index
- 45/100
- Enrollment
- 1,783
- Students per teacher
- 22.6:1
- Resource Index
- 21/100
- Enrollment
- 1,763
- Students per teacher
- 21:1
- Resource Index
- 40/100
Similar high schools in Philadelphia
6 comparable high schools (grades 9-12) serving the same city.
Northeast Hs
Standard public school
3,463 students 18.9:1 students per teacher
Lincoln Hs
Standard public school
2,472 students 17:1 students per teacher
Central Hs
Standard public school
2,329 students 20.1:1 students per teacher
Washington George Hs
Standard public school
1,755 students 15.8:1 students per teacher
Franklin Towne Chs
Standard public school
1,292 students 18.5:1 students per teacher
Fels Samuel Hs
Standard public school
1,255 students 17.7:1 students per teacher
Similar high schools statewide
Matched by enrollment size and by staffing ratio across all of Pennsylvania, not just this city - a different peer set than the local comparisons above.
Similar enrollment (~371 students)
Similar student-teacher ratio (~18.6:1)
Next steps
Verify locally before acting on Building 21's federal record.
- Compare Building 21 against another school. Compare schools
- Philadelphia City Sd's spending and staffing shape this school. District profile
- Confirm current enrollment and boundaries with the school. Choosing guide
Federal record (CCD 2024-25, CRDC 2021-22) - PlainSchools assigns no subjective rating; the composite quality score is a transparent, reproducible index computed from this cited federal data.
Frequently asked questions about Building 21
How many students attend Building 21?
Building 21 has 371 students enrolled. It is a high school in Philadelphia, PA.
What is the student-teacher ratio at Building 21?
The student-teacher ratio at Building 21 is 18.6:1, which is 37% higher than the Pennsylvania average of 13.6:1 and 18% higher than the national average of 15.7:1.
What percentage of students receive free lunch at Building 21?
100.0% of students at Building 21 are eligible for free lunch, compared to the Pennsylvania average of 58.1%.
What is the racial and ethnic makeup of Building 21?
The largest demographic group at Building 21 is African American at 91.4% of enrollment, in Philadelphia, PA.
What is the Resource Investment Index for Building 21?
Building 21 has a Resource Investment Index of 34/100 (typical reported resources relative to schools nationally) based on 5 factors: student-teacher ratio, counselor availability, attendance rates. Not a test-score or academic measure (national median ~41/100, see methodology).
How does Building 21 rank among high schools in Philadelphia?
By Resource Investment Index, Building 21 ranks #28 of 57 high schools in Philadelphia, PA. This compares federal resource and staffing data among local peers; it is not a test-score or academic ranking. See all high schools in Philadelphia on the city page.
Is Building 21 a good school?
Building 21 earns 34/100 on the Resource Investment Index, with class sizes larger than 96% of Pennsylvania schools. This is a resource snapshot, not an academic rating; see the Resource Investment Index question above for what the number does and doesn't measure.
What other schools are in Philadelphia City Sd?
Besides Building 21, Philadelphia City Sd also operates Northeast Hs (3,463 students), Lincoln Hs (2,472 students), and Central Hs (2,329 students). See the Philadelphia City Sd district page for the complete list.
Related tools
Every figure on PlainSchools is rendered directly from the source NCES, CRDC and F-33 federal records, no number is typed in by an editor. Each school's figures reflect its most recent NCES/CRDC submission on file. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of June 2026.