About

The ACT composite score is the arithmetic mean of four section scores - E (English), M (Math), R (Reading), and S (Science) - each scaled from 1 to 36, rounded to the nearest whole number. A single-point error in one section shifts the composite by 0.25, which can cross a rounding boundary and change the reported score. Colleges often publish median composite ranges; landing below the 25th-percentile cutoff of a target school statistically reduces admission probability. This calculator uses the official ACT percentile rank tables (2023-2024 national norms) and the College Readiness Benchmarks published by ACT, Inc. It approximates percentile rank by table lookup, not interpolation. Results assume standard-time, national testing conditions.

Formulas

The ACT composite score is defined as the arithmetic mean of the four mandatory section scores, rounded to the nearest integer:

Composite = round(E + M + R + S4)

The STEM score averages only Math and Science:

STEM = round(M + S2)

The ELA (English Language Arts) score requires the optional Writing section (W, scaled 2 - 12). ACT maps Writing to a 1 - 36 scale before averaging:

ELA = round(E + R + W_scaled3)

Where E = English (1 - 36), M = Math (1 - 36), R = Reading (1 - 36), S = Science (1 - 36), and W = Writing (2 - 12). College Readiness Benchmarks: English ≥ 18, Math ≥ 22, Reading ≥ 22, Science ≥ 23.

Reference Data

Composite Score	Percentile Rank	Competitiveness
36	99%	Top 1%
35	99%	Top 1%
34	99%	Top 1%
33	98%	Top 2%
32	96%	Highly Competitive
31	95%	Highly Competitive
30	93%	Highly Competitive
29	91%	Very Competitive
28	88%	Very Competitive
27	85%	Very Competitive
26	82%	Competitive
25	78%	Competitive
24	74%	Above Average
23	69%	Above Average
22	63%	Above Average
21	57%	Average
20	50%	Average (Median)
19	44%	Below Average
18	38%	Below Average
17	31%	Below Average
16	25%	Low
15	19%	Low
14	14%	Low
13	9%	Very Low
12	5%	Very Low
11	2%	Very Low
10	1%	Bottom 1%

Frequently Asked Questions

The composite is the sum of four section scores divided by 4, then rounded to the nearest integer using standard rounding (0.5 rounds up). For example, scores of 25 + 24 + 26 + 24 = 99, divided by 4 = 24.75, which rounds to 25. But 25 + 24 + 25 + 24 = 98, divided by 4 = 24.5, also rounds to 25. This means improving a single section by 1 point does not always change your composite.

ACT, Inc. defines benchmarks as the minimum section scores associated with a 50% probability of earning a B or higher in the corresponding first-year college course. The benchmarks are: English ≥ 18 (English Composition I), Math ≥ 22 (College Algebra), Reading ≥ 22 (Social Sciences), and Science ≥ 23 (Biology). Meeting all four indicates readiness across disciplines. Falling below even one benchmark signals a gap that may require remedial coursework.

The STEM score averages only Math and Science (2 sections instead of 4). It was introduced to give colleges and students a quick indicator of quantitative readiness. A student scoring 30 in Math and 20 in Science gets a STEM score of 25, which may misrepresent strength in either area individually. Always review section scores alongside the STEM aggregate.

No. The Writing section (scored 2-12) is reported separately and does not factor into the composite. It does, however, contribute to the ELA (English Language Arts) score, which averages English, Reading, and a scaled version of Writing. Some colleges require or recommend the Writing section, so check individual admission requirements.

The percentile ranks are based on the 2023-2024 ACT national norms, which represent the cumulative distribution of all test-takers in that cycle. Percentile ranks can shift slightly year to year as the test-taking population changes. A composite of 20 corresponds to approximately the 50th percentile nationally, meaning half of test-takers scored at or below that level.

Superscoring means selecting the highest section score from multiple test dates to form a new composite. ACT itself offers this through their official superscore report. However, not all colleges accept superscores. This calculator computes scores from a single sitting. To superscore, enter the highest section scores from across your test dates into the respective fields.

Median ACT ranges vary widely. Highly selective institutions (Ivy League, Stanford, MIT) typically report 25th - 75th percentile composites between 33 and 36. Large state universities often range from 22 to 28. A score of 30 or above (approximately 93rd percentile) is competitive at most institutions. Always cross-reference the specific school's Common Data Set for accurate admitted-student score ranges.