IQ percentiles explained
A percentile tells you what share of people you scored above — a 125 IQ is roughly the 95th percentile, meaning you outperformed about 95% of the reference group.
Updated:
Why IQ scores use a normal curve
IQ scores are designed to follow a normal distribution with a mean of 100 and a standard deviation of 15. That shape makes it easy to translate any score into a percentile: a score one standard deviation above the mean (115) sits near the 84th percentile, and two standard deviations (130) near the 98th.
Percentiles compress the differences at the extremes. Moving from IQ 130 to 145 covers as many percentile points as moving from 100 to 115 — but it represents far fewer people.
IQ to percentile conversion
| IQ score | Percentile (approx.) | Meaning |
|---|---|---|
| 70 | 2nd | Lower than about 98% of the group |
| 85 | 16th | Lower than about 84% of the group |
| 100 | 50th | The middle of the group |
| 115 | 84th | Higher than about 84% of the group |
| 120 | 91st | Higher than about 91% of the group |
| 125 | 95th | Higher than about 95% of the group |
| 130 | 98th | Higher than about 98% of the group |
| 145 | 99.9th | Higher than about 999 in 1,000 people |
Percentile of what group?
A percentile is only as meaningful as the group behind it. Clinical IQ tests use population norms; our dataset is built from online test-takers, who tend to be somewhat more test-interested and self-selected than the general population.
That is why the same raw performance can produce a different percentile depending on the reference group. When you share "95th percentile", it is worth knowing whether that refers to a national sample, a clinical norm, or the participants of a specific test.
Reading your result
Your result page on this site shows your score, its percentile in the dataset, and how you compare with groups such as your age band or education level. If you want to understand where the percentile sits on the classic scale, keep this chart handy.
Frequently asked questions
About the 91st percentile — higher than roughly 91% of the reference group.
Yes — the 99th percentile is roughly IQ 135 and above. It represents about one person in a hundred.
For test performance, yes, but percentiles say nothing about the traits that matter at work and in life — like persistence, curiosity, and collaboration.