An IQ score is not a raw count of right answers. It is a comparison: it shows where your result sits among people of your age. Modern tests such as the Wechsler scales (WAIS for adults, WISC for children) and the Stanford-Binet are designed so that the average score is 100 and the standard deviation is 15. That single design choice gives every IQ score a precise meaning.
IQ score chart
| IQ score | Classification | How rare |
|---|---|---|
| 145+ | Very gifted | Top 0.1% (about 1 in 740) |
| 130-144 | Very superior (gifted) | Top 2% (about 1 in 44) |
| 120-129 | Superior | Top 9% |
| 110-119 | High average | Top 25% |
| 90-109 | Average | Middle 50% |
| 80-89 | Low average | Bottom 25% |
| 70-79 | Borderline | Bottom 9% |
| Below 70 | Extremely low | Bottom 2% |
Classification names vary a little between tests and editions; these follow the common Wechsler-style bands.
The bell curve
IQ scores follow a normal distribution - the famous bell curve. About 68% of people score within 15 points of the average (85-115), and about 95% score within 30 points (70-130). Scores far from 100 in either direction become rapidly rarer.
IQ to percentile
Your percentile is the share of people who score lower than you. Here is how common IQ scores convert:
| IQ | Percentile | In a room of 100 people, you'd outscore |
|---|---|---|
| 85 | 16 | 15 |
| 90 | 25 | 25 |
| 95 | 37 | 36 |
| 100 | 50 | 50 |
| 105 | 63 | 63 |
| 110 | 75 | 74 |
| 115 | 84 | 84 |
| 120 | 91 | 90 |
| 125 | 95 | 95 |
| 130 | 98 | 97 |
| 135 | 99.0 | 99 |
| 140 | 99.6 | 99 |
| 145 | 99.9 | 99 |
What is a good IQ score?
Anything from 90 to 109 is average - and "average" here means you think just like most people around you. A score of 110 to 119 is above average, 120 to 129 is superior, and 130 or more places you in roughly the top 2%, the threshold used by the high-IQ society Mensa.
What IQ counts as "genius"?
There is no official genius line. In popular use, a score of 140 or more is often called genius level - about 1 person in 260 scores that high on a test with a standard deviation of 15. Famous "IQ scores" of historical figures are almost always estimates made long after the fact, so take them with a pinch of salt.
Why do different tests give different numbers?
Some older or online tests use a standard deviation of 16 or even 24, which stretches the same ability into bigger numbers. A "150" on a scale with SD 24 is roughly a 131 on the usual SD 15 scale. Always check which scale a score uses before comparing.
Where do you fall on the curve?
Take the free 20-question IQ test and see your score, your percentile and your room of 100.
Start the free IQ test