IQ 70
What does an IQ of 70 mean?
70 sits just inside the Borderline band, right on the line with Extremely Low. Here is what the score means, how rare it is, and why the label matters less than the range around it.
Short answer
An IQ of 70 is well below average. It is higher than about 2.3% of people, which puts it at the 2.3 percentile. About 1 in 44 people score 70 or lower, and the WAIS-IV labels it Borderline (70 to 79). It is 2 standard deviations below the mean of 100.
Specimen · IQ 70
70IQ
- Classification
- Borderline
- Percentile
- 2.3
- Rarity
- 1 in 44
- z-score
- −2.00
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| Percentile | 2.3 |
| Share scoring 70 or lower | 2.3% (about 1 in 44) |
| Out of 1,000 people | about 23 at or below |
| Standard deviations from the mean (z) | -2.00 |
| WAIS-IV classification | Borderline (70 to 79) |
| Same percentile, SD 16 scale | 68 |
| Same percentile, SD 24 scale | 52 |
What an IQ of 70 means on the scale
Modern IQ tests report a deviation IQ: scores are standardized so the mean is 100 and the standard deviation is 15 within each age group (Wikipedia: Intelligence quotient). On that scale 70 is 2 standard deviations below the mean. It sits exactly two standard deviations from the mean, at the edge of the 70 to 130 range where about 95% of people score. (the 68-95-99.7 rule)
In a room of 30 people your age, fewer than 1 (about 1 in every 44 groups of 30) would be expected to score 70 or lower. Put another way, about 98 out of every 100 people score above 70.
The Borderline band: 70 to 79
The WAIS-IV uses the label Borderline for scores from 70 to 79 (Wikipedia: IQ classification), between about one and a third and two standard deviations below the mean. About 6.5% of people score in this range.
The label names a score range on one test. It is not a diagnosis, and on a short online test it is not even a reliable placement: tiredness, an unfamiliar format, a small screen or simply not taking the test seriously can each pull a score into this range. 70 is 1 point above the line at 70 that separates this band from the lowest one.
Where 70 sits inside the band
70 is the first score in the Borderline band (70) and 9 points below its ceiling (79). No one in this band scores below 70, so it is at the very bottom of the group that shares its label.
Clinical IQ scores carry measurement error of around plus or minus 5 points at 95% (Wechsler, 2008). A measured 70 is consistent with a true score anywhere from 65 to 75, which is the 0.98 to 4.8 percentile. That range spans two labels, Extremely Low and Borderline, so the band name is the least certain part of the result. A short online test has a wider range than a clinical one, so read any single number as the middle of a span.
What an IQ of 70 does and does not predict
If a careful, supervised test produces a score in this range, it can help explain why some kinds of tasks feel harder. It does not define what a person can do, learn or become.
Across large groups, the links are real. General intelligence at age 11 correlated 0.81 with exam results at 16 in about 70,000 English children (Deary, Strand, Smith & Fernandes, 2007), a review of 85 years of workplace research put the link with job performance at 0.51 (Schmidt & Hunter, 1998), and a 2007 meta-analysis found correlations of about 0.56 with education and 0.23 with income (Strenze, 2007). Those describe tendencies across many people. None of them let anyone predict an individual life from one number. The guide to what IQ predicts explains what a correlation of that size means.
Same score, different tests
Older Stanford-Binet forms used a standard deviation of 16, and the Cattell Culture Fair III scale uses 24 (Wikipedia: IQ classification). The same percentile as 70 on a standard-deviation-15 test reads as about 68 on the first and 52 on the second, so check which scale a number is on before comparing scores from different tests.
Nearby scores
| IQ | Percentile | Rarity | Classification |
|---|---|---|---|
| IQ 67 | 1.4 | 1 in 72 | Extremely Low |
| IQ 68 | 1.6 | 1 in 61 | Extremely Low |
| IQ 69 | 1.9 | 1 in 52 | Extremely Low |
| IQ 71 | 2.7 | 1 in 38 | Borderline |
| IQ 72 | 3.1 | 1 in 32 | Borderline |
| IQ 73 | 3.6 | 1 in 28 | Borderline |
| IQ 75 | 4.8 | 1 in 21 | Borderline |
| IQ 80 | 9.1 | 1 in 11 | Low Average |
| IQ 85 | 15.9 | 1 in 6 | Low Average |
IQ 69 · IQ 71 · every score on the IQ chart · IQ percentile calculator · the seven classification bands
Sources
- Intelligence quotient. Wikipedia. en.wikipedia.org/wiki/Intelligence_quotient
- IQ classification. Wikipedia. en.wikipedia.org/wiki/IQ_classification
- 68-95-99.7 rule. Wikipedia. en.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule
- Wechsler, D. (2008). WAIS-IV Technical and Interpretive Manual. Pearson.
- Deary, I. J., Strand, S., Smith, P., & Fernandes, C. (2007). Intelligence, 35(1), 13-21. doi.org/10.1016/j.intell.2006.02.001
- Schmidt, F. L., & Hunter, J. E. (1998). Psychological Bulletin, 124(2), 262-274. doi.org/10.1037/0033-2909.124.2.262
- Strenze, T. (2007). Intelligence, 35(5), 401-426. doi.org/10.1016/j.intell.2006.09.004