The IQ score scale: what the numbers mean
On professional tests, the average is set to 100. Whether a score counts as good depends on what you compare it with, and that comparison only works with a normed test.
Why the average is 100
Publishers of professional tests give the test to a large representative sample and set the scores so that the middle of that group is 100. Most modern tests use a standard deviation of 15, which is why the same ranges appear in many charts.
How much of the scale each range covers
The table shows the shares that follow from a normal distribution with an average of 100 and a standard deviation of 15. They describe the mathematical scale of normed tests. They are not measurements from this site.
| Score range | Share of the scale |
|---|---|
| Below 70 | about 2% |
| 70 to 85 | about 14% |
| 85 to 115 | about 68% |
| 115 to 130 | about 14% |
| Above 130 | about 2% |
What is a good IQ score?
There is no official line between good and bad. About two thirds of the scale lies between 85 and 115, so scores there are the most common. Labels such as above average vary between test publishers.
Why our number does not fit this table
Our estimate comes only from your share of correct answers and has not been compared with a tested group. So a 115 here does not place you anywhere in this table. The real meaning of our number is on the method page.