Estimate IQ from an ACT composite score with this ACT to IQ calculator, which converts scores from 1 to 36 into an approximate IQ equivalent.
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ACT To IQ-Equivalent Formula (Estimate)
The following formula is used to estimate an IQ-equivalent score from an ACT Composite score by matching standardized scores (z-scores). This is not an official conversion and results depend on the assumed ACT mean and standard deviation.
Variables:
- IQeq is an estimated IQ-equivalent score on the common IQ scale (mean 100, standard deviation 15), not an official IQ result
- ACT is the ACT Composite score (typically 1–36)
To estimate an IQ-equivalent from an ACT score, compute the ACT z-score using an approximate ACT mean (20.8) and standard deviation (5.2), then convert that z-score to the IQ 100±15 scale.
| ACT Score | IQ-Equivalent (estimate) |
|---|---|
| 10 | 68.8 |
| 12 | 74.6 |
| 14 | 80.4 |
| 15 | 83.3 |
| 16 | 86.2 |
| 18 | 91.9 |
| 20 | 97.7 |
| 21 | 100.6 |
| 22 | 103.5 |
| 24 | 109.2 |
| 25 | 112.1 |
| 26 | 115.0 |
| 28 | 120.8 |
| 30 | 126.5 |
| 31 | 129.4 |
| 32 | 132.3 |
| 33 | 135.2 |
| 34 | 138.1 |
| 35 | 141.0 |
| 36 | 143.8 |
| Method used: IQeq ≈ 100 + 15 × (ACT − 20.8) ÷ 5.2 (assumes ACT mean 20.8, SD 5.2; IQ mean 100, SD 15). Inverse: ACT ≈ (((IQ − 100) ÷ 15) × 5.2) + 20.8. ACT Composite range: 1–36. | |
How to Estimate ACT To IQ-Equivalent?
The following steps outline how to estimate an IQ-equivalent score from an ACT Composite score using a standardized-score (z-score) approach.
- First, determine the ACT Composite score (typically 1–36).
- Compute the ACT z-score: z = (ACT − 20.8) ÷ 5.2 (using approximate norms).
- Convert to the IQ-equivalent scale: IQeq ≈ 100 + 15 × z.
- The obtained value is an estimate of an IQ-equivalent score (not an official IQ test result).
- After inserting the ACT score and performing the calculations, you can check your answer with the calculator above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
ACT Composite score = 25 (IQ-equivalent estimate ≈ 112.1)
