IQ 63: what it means, percentile and how rare it is
An IQ score of 63 is higher than about 0.68% of people, which puts it in the 1st percentile. Roughly 1 in 147 people score lower than 63. On the WISC-V it is classified as Extremely Low.
- Percentile
- 1st
- Higher than
- 0.68%
- People scoring lower
- 1 in 147
- WISC-V classification
- Extremely Low
What does an IQ of 63 mean?
Scores of 69 and below are in the Extremely Low range, more than two standard deviations below the mean. About 2% of people score below 70.
On a professionally administered test, a score in this range is one of the things clinicians consider when assessing intellectual disability (DSM-5-TR: intellectual developmental disorder). But IQ alone never makes the diagnosis: it also requires clear difficulties with everyday adaptive skills that began during development, and the level of support someone needs is judged by those skills, not by the IQ number.
If you got a score like this on an online test, treat it with great caution. Tiredness, distraction, a language barrier, unfamiliar question types or simply rushing can pull a self-administered score down a long way. If you have real concerns, a psychologist can carry out a proper assessment.
IQ 63 on other scales and tests
Different tests spread scores differently. The same rank as an IQ of 63 on an SD-15 test gives these numbers elsewhere:
| Scale | Equivalent score | Classification |
|---|---|---|
| SD 15: WISC-V, WAIS, Stanford-Binet 5 | 63 | Extremely Low |
| WAIS-IV (older label) | 63 | Extremely Low |
| Stanford-Binet 5 | 63 | Mildly impaired or delayed |
| SD 16: older Stanford-Binet, Cattell Culture Fair | 61 | – |
| SD 24: Cattell III B | 41 | – |
How precise is an IQ score of 63?
No test measures IQ exactly. On individually administered tests such as the WAIS, the full-scale score comes with a 95% confidence interval of roughly ±5 points, so a result of 63 is best read as "probably somewhere between 58 and 68". Scores can also shift a few points between different tests or after a few years.
Online tests, including ours, are self-assessments. They are useful for curiosity and practice, but they are not a substitute for an assessment by a psychologist.
IQ scores near 63
| IQ score | Percentile | Higher than | WISC-V classification |
|---|---|---|---|
| 58 | 0.26th | 0.26% | Extremely Low |
| 59 | 0.31th | 0.31% | Extremely Low |
| 60 | 0.38th | 0.38% | Extremely Low |
| 61 | 0.47th | 0.47% | Extremely Low |
| 62 | 1st | 0.56% | Extremely Low |
| 63 | 1st | 0.68% | Extremely Low |
| 64 | 1st | 0.82% | Extremely Low |
| 65 | 1st | 0.98% | Extremely Low |
| 66 | 1st | 1.2% | Extremely Low |
| 67 | 1st | 1.4% | Extremely Low |
| 68 | 2nd | 1.6% | Extremely Low |
Check another IQ score
For example 98 for the top 2%.
- Percentile
- 1st
- Higher than
- 0.68%
- People scoring lower
- 1 in 147
- Classification (WISC-V)
- Extremely Low
IQ 63: frequently asked questions
Is an IQ of 63 good?+
It is well below the average of 100: higher than about 0.68% of people. On a professional test, a score like this would lead a psychologist to look closely at everyday skills too. On an online test, it is far more likely to reflect the testing situation than a person's real ability.
What percentile is an IQ of 63?+
An IQ of 63 is in the 1st percentile on a scale with mean 100 and standard deviation 15. It is higher than about 0.68% of people and lower than about 99.32%.
How rare is an IQ of 63?+
Roughly 1 in 147 people score lower than 63. In a group of 1,000 people you would expect about 6.8 to score lower.
Does an IQ of 63 mean intellectual disability?+
Not on its own. A score in this range on a professionally administered test meets the intellectual part of the DSM-5-TR criteria, but a diagnosis also requires significant difficulties with everyday adaptive skills that began during development, assessed by a qualified professional. An online test score can never establish it.