ACT to IQ converter

Like every score-to-IQ conversion, this is an estimate. The ACT correlates about .77 with a general-ability score in the best published study, which is strong but leaves plenty of room for people who are sharper or weaker than their score suggests. If the ACT were a perfect IQ measure, a 28 would mean IQ 119.

Every ACT score, from the same model as the calculator. The likely range covers about four in five people at that score. The last column is the IQ you would get if the ACT measured IQ perfectly, which is the number most other charts show.

Going the other way, this is the ACT score people at each IQ typically get. Scores at the same IQ vary a lot, so the range matters more than the middle figure. Full IQ to ACT chart.

The ACT tests English, maths and reading, and historically science reasoning, in a timed multiple-choice format. It is closer to a school-achievement test than the SAT is: the maths section assumes algebra, geometry and some trigonometry, and the English section tests grammar conventions.

Even so, ACT scores track general ability closely. Koenig, Frey and Detterman (2008) matched ACT composites to a general-ability score built from the ASVAB for 1,075 people in a national US sample and found a correlation of .77. In a smaller sample of 149 students who also took Raven's Advanced Progressive Matrices, the correlation was .61.

The gap between .77 and .61 is informative. The ACT relates less strongly to a pure reasoning test than to a broad battery that also samples vocabulary and arithmetic. That is one reason this converter uses a correlation of .72 rather than the higher figure.

From 2025 the ACT was shortened and Science became optional. The composite for most students is now the average of English, Math and Reading only. ACT has not yet published national norms for that three-section composite.

This converter uses the Class of 2025 profile, which for most students still reflects the four-section composite. If you took the newer version, treat the result as approximate. The direction and the general size of the estimate should hold, but a point or two in either direction is inside the uncertainty anyway.

One more thing changes the picture: several US states have every student take the ACT at school, so the pool includes many students who would not have chosen to sit it. That pulls the average score down and makes the test-taker pool closer to the general population than the pool for a voluntary test.

Neither is clearly better as a stand-in for IQ. The SAT has more published evidence linking it to general ability, largely because of the older studies, but the ACT correlates about as strongly in the study that measured it. If you have both scores, the two estimates should land within a few points of each other; use the SAT to IQ converter for the other one and treat any gap as noise.

Mensa is a useful reference. American Mensa accepted an ACT composite of 29 for tests taken before September 1989 and accepts no ACT scores after that date. A 29 today would sit at about the 91st percentile of test-takers, so that historical bar corresponded to a much narrower group than the modern pool.

Percentiles compare you with other 2025 test-takers. The estimated IQ column shows the most likely value, with the likely range in brackets.

There is no official ACT to IQ conversion. ACT, Inc. does not publish one. What we can do honestly is treat the ACT as a good but imperfect signal of general ability. We place your score among ACT test-takers, assume how able that group is on average, and use the correlation between the two to predict the most likely IQ. Because the correlation is below 1, high and low scores are pulled towards the middle. That is why the estimate comes with a range.

Evidence grade: moderate. A published comparison exists, in the same research group and design as the SAT study. It used a general-ability score from a military battery and a pre-2025 ACT, not a Wechsler test on the current exam.

Published facts we used

• ACT composite and ASVAB-derived general ability: r = .77 (N = 1,075; Koenig, Frey and Detterman, 2008).
• ACT composite and Raven's Advanced Progressive Matrices: r = .61 (N = 149).
• Class of 2025 composite mean 19.4, SD 5.9, N = 1,380,130 (ACT profile report).
• Cumulative percentiles for each composite score.

Assumptions we made

• Mean IQ of ACT test-takers: 101. About a third of US graduates take the ACT, and several states test every student, which keeps the pool close to the general population.
• IQ spread among test-takers: SD 14.
• Correlation between ACT and IQ among test-takers: .72, between the two published values and lowered for selection.