Convert IQ ↔ ACT
How the conversion works
IQ and ACT scores are normalised on bell-curve distributions. The conversion maps a person's standing in one distribution to the equivalent standing in the other.
- IQ: mean 100, standard deviation 15.
- ACT composite: mean ≈ 21, standard deviation ≈ 5, based on ACT national score reports.
IQ-equivalent = (target − meantarget) / SDtarget × 15 + 100
target-equivalent = (IQ − 100) / 15 × SDtarget + meantarget
Common IQ ↔ ACT reference table
| IQ | ACT | Percentile |
|---|---|---|
| 85 | 16 | ~16th |
| 90 | 18 | ~25th |
| 100 | 21 | ~50th |
| 110 | 24 | ~75th |
| 120 | 27 | ~91st |
| 130 | 30 | ~98th |
| 140 | 33 | ~99.6th |
Important caveats
- The ACT measures developed academic skills; IQ measures general cognitive ability. They correlate around 0.7, not 1.0, so an individual can plausibly score higher on one than the other.
- Extreme-tail conversions are less reliable because both tests have fewer calibration cases there.
- No score entered here is stored, submitted, or connected to an account.
Related tools
IQ percentile calculator · IQ to SAT converter · IQ to GRE converter · IQ score chart
Cite this converter
Editorial content and curation are released under CC BY-SA 4.0. This converter is part of the What's Your IQ educational resources.