IQ Percentile Calculator & Chart

Complete IQ percentile chart: IQ 55 to 160

Every whole score, its percentile, how rare it is, and the classification band it falls in. Percentiles are calculated on a normal distribution with a mean of 100 and a standard deviation of 15, the scale used by the Wechsler tests and by most modern online tests. "Top 1 in 44" means about one person in 44 scores at or above that level; below 100 the column reads the other way, as "Bottom 1 in".

Scores are rounded to the nearest whole percentile between the 1st and 99th, and shown to more decimal places in the tails where the differences matter. For the meaning of each classification band — and for the compact range-by-range IQ score chart — see the IQ scale guide. The statistics behind percentiles are worked through further down this page.

Convert percentile to IQ

Going the other way — from a percentile rank to a score — uses the same normal distribution in reverse. The 90th percentile is about IQ 119, the 95th is about 125, and the 99th is about 135.

IQ values are rounded to the nearest whole score. Because scores are discrete and percentiles are continuous, converting back and forth will not always return the exact number you started with — the 98th percentile maps to IQ 131, while IQ 130 maps to the 97.7th percentile.

IQ rarity chart: how rare is each score?

Rarity is the same statistic as the percentile, expressed as a headcount. The right-hand column is the number of people expected to reach each score in a city of one million.

Treat the highest rows as arithmetic, not measurement. The normal curve can be extended indefinitely, but no standardized test is normed on enough people to place someone at 1 in 31,600 with confidence — which is why claims about record-breaking scores deserve scepticism. See the highest IQ ever recorded for what the evidence actually supports.

What a specific IQ score means

An IQ score is a rank, not a quantity of intelligence. It says how your performance compared with the people the test was normed on — nothing about a fixed inner value. Reading any single score means reading three things together: the percentile, the classification band, and the error around it.

• Average (90–109): about half of all scores. An IQ of 100 is the exact midpoint, and 95 or 105 is a thoroughly ordinary result rather than a meaningful gap.
• High Average (110–119): roughly the 75th to 91st percentile — common among people in cognitively demanding work.
• Superior (120–129): the 91st to 97th percentile, about one person in eleven at the lower edge.
• Very Superior (130+): the top ~2%, the usual gifted and Mensa cutoff.
• Low Average (80–89) and Borderline (70–79): bands describing test performance only. They are conventions, not diagnoses, and no score by itself establishes anything about a person's functioning.

The error matters as much as the band. A well-constructed test typically carries a confidence interval of several points, so adjacent scores — 118 and 121, say — often reflect the same underlying performance despite falling in different bands. Read the range, not the point. For more, see how accurate IQ tests are and what counts as a good IQ score.

Why percentiles beat raw scores

A raw IQ number only means something because of the population behind it. Saying "my IQ is 124" is really shorthand for "I scored higher than about 94.5% of the norming sample." The percentile is the actual information; the IQ number is a convenient encoding of it. Percentiles have three practical advantages:

• They are scale-independent. Some tests historically used SD 16 (older Stanford-Binet) or SD 24 (Cattell). An IQ of 148 on the Cattell scale and 130 on the Wechsler scale are the same 98th-percentile performance — the percentile exposes an equivalence the raw numbers hide.
• They map directly to real-world selection. Admissions committees, gifted programs and high-IQ societies think in terms of "top 2%" or "top 0.1%", not points.
• They discourage over-reading small gaps. The 5-point difference between IQ 100 and 105 spans 13 percentile points, while the same 5 points between 145 and 150 spans fewer than 0.1 — near the extremes, small score differences are mostly measurement noise.

Common percentile cutoffs

Mensa is the best-known example: membership requires a score at or above the 98th percentile on an approved, supervised test. Note that Mensa itself defines the bar as a percentile, not an IQ number — precisely because different tests use different scales.

A worked example: converting IQ 122 to a percentile

Suppose you scored 122 and want to check the table by hand. The conversion takes three steps. First, compute the z-score: (122 − 100) ÷ 15 = 1.47 standard deviations above the mean. Second, look up the cumulative probability for z = 1.47 on the standard normal curve, which is about 0.929. Third, read that as a percentile: roughly the 93rd— higher than about 93% of the population, or about 1 person in 14 scoring at or above. The same recipe works for any score on any test, as long as you know that test's mean and standard deviation.

Scores below 100 work identically in the other direction. An IQ of 88 gives z = −0.8, which is about the 21st percentile — higher than roughly 21% of people, lower than 79%. There is nothing special about the lower half of the curve; it is the same distribution mirrored.

How this calculator works

IQ scores follow a normal distribution with a mean of 100. Most modern tests use a standard deviation of 15, so the calculator converts your score to a z-score (how many standard deviations from the mean) and reads the percentile from the normal curve. An IQ of 115 is one standard deviation above the mean — the 84th percentile — while 130 is two standard deviations up, the 98th percentile.

Some tests report on different scales: the Cattell scale uses a standard deviation of 24, which is why a "Cattell 148" equals a "Wechsler 130." Use the scale selector to convert. For the full background, see our guides to the IQ scale and score chart and how IQ is calculated.

Frequently asked IQ percentile questions

Don't know your IQ?

Take the IQ Revealed 40-question assessment — matrix-reasoning questions, about 15 minutes — and get your score, percentile and a five-ability cognitive profile.