IQ Level Chart: Every Score From 40 to 160 With Percentile, Rarity and Level

An IQ level chart maps each score on the standard scale (mean 100, standard deviation 15) to its percentile, its rarity and its level. The chart below runs from 40 to 160 in steps of 5. About 68% of people score between 85 and 115, about 95% between 70 and 130, and about 1 person in 740 scores 145 or higher. A chart shows where a score sits on a distribution; it does not rank a person’s worth, and it is only as good as the test that produced the score.

• Average: 100 is the 50th percentile; 90 to 109 is the Average band on the main tests and holds about half of all people.
• Spread: about 68% of people score between 85 and 115 and about 95% between 70 and 130.
• Tails: about 1 person in 44 scores 70 or lower and about 1 in 44 scores 130 or higher.
• Scale: the chart assumes a standard deviation of 15; older Stanford-Binet scales use 16 and Cattell uses 24.
• Limit: a chart does not say which test produced a score, and a score is a range of about 5 points either side.

IQ chart: score, percentile and rarity

Find your score in the first column. The percentile is the share of people scoring at or below it; the rarity column says how many people score as low or lower (below 100) or as high or higher (above 100). The levels in the last column follow the simplified ranges in our guide to IQ ranges, so they are descriptions, not diagnoses. Labels on the main clinical tests differ slightly and are listed in IQ classifications.

The rows around 100 are the busiest part of the chart: moving from 90 to 110 crosses half of all people. The rows at either end are the least reliable, because very few people in any norm sample score so far from the average. For single scores see our guides to an IQ of 70, an IQ of 85, an IQ of 100, an IQ of 115 and an IQ of 130.

How many people fall in each IQ level?

The second chart turns the levels into head counts. The last two columns say how many people in 1,000 fall in each level and how many pupils to expect in a class of 30.

The Average range, 85 to 114 here, holds about two thirds of everyone, so most classrooms, workplaces and families are built from people in the middle of the chart. In a class of 30 that is about 20 pupils, and fewer than one pupil, on average, at either extreme (130 or above, or below 70).

How do you read an IQ level chart?

• Check the scale. Most modern tests use a standard deviation of 15. A printed score from an older Stanford-Binet (16) or a Cattell scale (24) must be converted first (standard deviation 15 versus 16 and the IQ score converter).
• Read a band, not a point. A score carries a standard error of about 2 to 3 points, so read 100 as roughly 95 to 105 (an IQ score is a range, not a number).
• Use the percentile. The percentile does not depend on the label and travels between charts; the IQ percentile calculator gives it for any score.
• Use the right label. Wechsler, Stanford-Binet and Woodcock-Johnson name the bands differently (for example, 110 to 119 is High Average on the Wechsler and Stanford-Binet tests). Our guides to the Stanford-Binet and the Woodcock-Johnson give theirs.

How do other score scales line up with the IQ chart?

Many school and work tests report standard scores on other scales, and each converts to IQ because all of them are the same bell curve with a different ruler. A T-score has a mean of 50 and a standard deviation of 10, a Wechsler subtest scaled score has a mean of 10 and a standard deviation of 3, and a stanine splits the curve into nine bands with a mean of 5. The first table lines the first two up with IQ; the second gives the IQ range of each stanine.

So a stanine of 5 covers IQs of about 96 to 104, a scaled subtest score of 7 sits at an IQ-equivalent of 85, and a T-score of 60 is the 84th percentile, the same as an IQ of 115. For worked examples see turning an IQ into standard units, CAT4 scores, ISEE scores and CCAT scores. College tests are covered in SAT score to IQ and ACT score to IQ, and military tests in ASVAB and AFQT to IQ.

Is there a different IQ chart for children?

No: the scale is the same, but the score is compared with children of the same age. A 10-year-old scoring 115 and an adult scoring 115 are both at the 84th percentile of their own age group. Old child charts used ratio IQ, mental age divided by chronological age times 100, which does not give the same percentiles at every age (see IQ and mental age). For how raw performance changes with age, see IQ and age and the IQ scale by age.

What does an IQ chart not tell you?

It does not say what produced the score, how reliable it is or what the person can do. Test scores correlate .56 with educational attainment, .43 with occupational level and .20 with income in a meta-analysis of longitudinal studies (Strenze, 2007). Squared, those say how much of the spread in an outcome goes with the score: about 31%, 18% and 4%. Most of the variation sits outside the test, so a level on a chart shifts the odds and sets no ceiling. Our guide to what an IQ test score really means explains how to read a result, and do IQ tests really work covers accuracy.

Quick answers about the IQ level chart

• What is a good IQ level? Anything from 90 to 109 is Average on the main tests, and half of all people score there. Whether a score is “good” depends on what it is for.
• What is the average IQ level? 100 on the standard scale, by construction.
• What IQ level is gifted? About 130 and above, the top 2% (see gifted cut-off scores).
• What is the lowest and highest level on the chart? Charts usually run from about 40 to about 160, because tests cannot measure reliably beyond them.
• Are online IQ levels accurate? Only if the test has a published norm sample; otherwise the number cannot be placed on the chart.

Sources

• Strenze, T. (2007): Intelligence and socioeconomic success: a meta-analytic review of longitudinal research, Intelligence, 35(5), 401-426.
• Percentile, rarity and head-count figures are computed from the normal distribution. The levels follow our own guides to IQ ranges and IQ classifications, which cite the test manuals.