An IQ score on its own is just a number. What most people really want to know is: how many people score lower than me? That is exactly what a percentile tells you. An IQ of 115 sits at about the 84th percentile, meaning you scored higher than roughly 84 out of every 100 people your age. An IQ of 130 sits at about the 98th percentile.
Below you will find a complete IQ percentile chart, an explanation of how the numbers are calculated, and a few common mistakes to avoid when reading your own result.
IQ percentile chart
Modern IQ tests are scaled so that the average score is 100 and the standard deviation is 15. Because scores follow a normal distribution (the familiar bell curve), every IQ score maps to a fixed percentile:
| IQ score | Percentile | Rarity (people scoring this high or higher) |
|---|---|---|
| 70 | 2nd | About 98 in 100 |
| 80 | 9th | About 91 in 100 |
| 85 | 16th | About 84 in 100 |
| 90 | 25th | About 3 in 4 |
| 95 | 37th | About 2 in 3 |
| 100 | 50th | 1 in 2 |
| 105 | 63rd | About 1 in 3 |
| 110 | 75th | About 1 in 4 |
| 115 | 84th | About 1 in 6 |
| 120 | 91st | About 1 in 11 |
| 125 | 95th | About 1 in 21 |
| 130 | 98th | About 1 in 44 |
| 135 | 99th | About 1 in 100 |
| 140 | 99.6th | About 1 in 260 |
| 145 | 99.87th | About 1 in 740 |
| 150 | 99.96th | About 1 in 2,300 |
| 160 | 99.997th | About 1 in 31,500 |
Percentiles in this table are rounded and assume a test with a standard deviation of 15, which is what the Wechsler scales and most modern tests use.
What is an IQ percentile?
A percentile tells you the percentage of people in a reference group who scored below you. If you are at the 75th percentile, you scored higher than 75% of the comparison group and lower than about 25%.
Two details matter here:
- The reference group is your age group. IQ tests compare you with people of the same age, so a percentile describes your standing among your peers, not among everyone alive.
- A percentile is not a percentage of questions answered correctly. Being at the 90th percentile does not mean you got 90% of the questions right. It means you outperformed 90% of the comparison group.
How IQ scores convert to percentiles
The conversion comes straight from the bell curve. With a mean of 100 and a standard deviation of 15:
- About 68% of people score between 85 and 115 (within one standard deviation of the average).
- About 95% score between 70 and 130 (within two standard deviations).
- About 99.7% score between 55 and 145 (within three standard deviations).
Each 15-point step away from 100 is one standard deviation. That is why the percentiles change quickly near the middle of the scale and slowly at the extremes: going from 100 to 115 moves you past 34% of the population, while going from 130 to 145 moves you past only about 2%.
Why the same percentile can mean different scores
Not every test uses a standard deviation of 15. Some older or specialised tests use 16 or even 24. On those tests, the same percentile corresponds to a different number. For example, the 98th percentile is around 130 on a test with SD 15, about 132 on a test with SD 16, and about 148 on a test with SD 24.
This is one reason you should never compare raw IQ numbers from different tests without checking how each one is scaled. The percentile is the more honest way to compare.
Common IQ percentile questions
What percentile is an IQ of 120?
About the 91st percentile. Roughly 1 in 11 people score 120 or higher.
What percentile is an IQ of 130?
About the 98th percentile, placing you in the top 2% of your age group. This is the usual threshold for "very superior" on the Wechsler classification.
What percentile is an IQ of 140?
About the 99.6th percentile, or roughly 1 in 260 people.
What percentile is an average IQ?
An IQ of 100 is exactly the 50th percentile. However, the whole range from 90 to 109 is considered average, which covers roughly the 25th to the 73rd percentile.
How to read your own percentile
- Look at the range, not just the point. Every test has some measurement error. A score of 118 is better read as "somewhere around 113 to 123", which spans roughly the 81st to the 94th percentile.
- Check the test's norms. A percentile is only as good as the reference group it is based on. Recently normed tests give more accurate comparisons.
- Remember what it measures. IQ percentiles describe performance on reasoning tasks on the day you took the test. They say nothing about creativity, motivation or character.
For a detailed look at what each score band means, see our guide to IQ scores and IQ levels, or read what your IQ score is telling you. Want to find out where you stand? Take our IQ test and see your score and percentile ranking.
