IQ Percentile Calculator
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How the percentile is calculated
IQ scores are built to follow a normal distribution — the familiar bell curve — centred on a mean of 100 with a standard deviation of 15. To turn a score into a percentile, the calculator measures how many standard deviations you are from the mean, then reads off the area under the curve below that point. That area is the share of people your score sits above.
Because the curve is densest in the middle, a few points near 100 move your percentile more than the same few points out at the tails. One wrinkle worth knowing: not every test uses the same spread. Most modern tests, including the Wechsler scales, use a standard deviation of 15; some, such as the older Stanford-Binet, use 16, which nudges the same score to a slightly different percentile. The calculator lets you switch between the two so your number is read on the right scale.
Score bands and what they mean
Every score falls into one of six interpretation bands. Each band's percentile span is derived from the very same bell curve the calculator uses, so the label and the percentile always agree.
| IQ Range | Percentile | Classification |
|---|---|---|
| 130–145 | 98th–99th | Exceptional |
| 115–129 | 84th–97th | Superior |
| 101–114 | 53rd–82nd | Above Average |
| 85–100 | 16th–50th | Average |
| 70–84 | 2nd–14th | Low Average |
| 60–69 | 1st–2nd | Below Average |
Worked examples
Here is the same math applied to three scores people ask about most, on the default standard deviation-15 scale.
| IQ score | Percentile | Rarity |
|---|---|---|
| 120 | 91st | 1 in 11 |
| 130 | 98th | 1 in 44 |
| 145 | 99th | 1 in 740 |
Notice the percentile flattens near the top while the rarity keeps climbing — that is why the calculator reports both. To get here without a score, take the free IQ test first.
Frequently asked questions
What percentile is an IQ of 120?
An IQ of 120 on the standard deviation-15 scale sits at the 91st percentile — you would score above roughly nine in ten people, a rarity of about 1 in 11. On a standard deviation-16 scale the same 120 reads a little lower, around the 89th percentile.
What percentile is an IQ of 130?
An IQ of 130 lands at the 98th percentile — the top few percent, or about 1 in 44. That is the neighbourhood of the common “top 2%” high-IQ-society threshold, though each society tests on its own terms.
What percentile is an IQ of 145?
An IQ of 145 is the 99th percentile — the calculator caps the percentile there, but rarity keeps climbing: 145 is roughly 1 in 740. Percentiles round off at the extremes, which is exactly why we also show the rarity figure.
Which standard deviation should I choose?
Match it to the test that gave you the score. The Wechsler scales use 15, so that is the sensible default; some tests, like the older Stanford-Binet, use 16. The same raw standing reads a couple of points of percentile apart between the two, so picking the wrong scale skews the result.
Keep reading
Want to understand what your number actually means? These guides go deeper.