IQ Score Ranges Explained: Chart, Percentiles & Famous IQs

The IQ scale at a glance

IQ scores are designed so that the average is exactly 100, with a standard deviation of 15. That means most people cluster near the middle, and the very high and very low ends are rare. Here's how the population actually distributes:

Chart based on a normal distribution with mean 100 and standard deviation 15 — the standard scoring used by tests like the WAIS-IV and Stanford–Binet.

What each range means

Below 70 — significantly below average (~2%)

This range is used in clinical contexts to identify intellectual disability, but only alongside a full assessment of adaptive functioning. A score alone never tells the whole story.

70–84 — below average (~14%)

Often called "borderline." People in this range can live fully independent lives but may find timed academic tasks more challenging. Most are within the normal range for everyday function.

85–114 — average (~68%)

The vast majority of the population sits here. Within this band there's enormous variation in how people think, work and succeed — IQ predicts only part of life outcomes. Personality, effort, opportunity and emotional skills matter at least as much.

115–129 — above average (~14%)

Common among people who excel academically and in cognitively demanding professions. A score of 120 puts you roughly in the top 10% of the population.

130–144 — gifted (~2%)

The threshold for most "gifted" programs and for membership in Mensa (the 2nd percentile and above). Most very successful scientists, mathematicians and chess players score in this range.

145+ — highly gifted / genius (~0.3%)

Above 145, scores get statistically noisy because there aren't many people in the sample used to calibrate the test. Differences between, say, a 165 and a 175 score are mostly meaningless. The numbers exist, but their precision does not.

Percentile lookup

If you took an IQ test and got the number below, here's roughly where you'd rank:

High-IQ society thresholds

Estimated IQs of famous historical figures

Almost every IQ figure attached to a historical person is an estimate, not a measured score. The most-cited research is Catharine Cox's 1926 study, which scored 300 historical geniuses based on their childhood writings and accomplishments. Treat these numbers as folklore with a grain of truth — interesting, not authoritative.

Sources: Cox (1926), Mensa records, Guinness World Records archives, biographies and self-reported figures from interviews. Many of these numbers are disputed.

What IQ doesn't tell you

IQ measures some things — reasoning speed, working memory, pattern recognition — and ignores almost everything else that shapes a life. It says nothing about creativity, drive, empathy, judgment, persistence or wisdom. Plenty of people with average IQs achieve extraordinary things; plenty of high-IQ people accomplish very little.

Use it as a snapshot of one slice of cognition, not a verdict on a person.

Find out your own score

The fastest way to see roughly where you land is to take a quick IQ test. Better yet, use the result as a baseline and re-take it in a few months after some consistent brain training to see how the trainable components of cognition shift.

Frequently asked questions