Guide · Reading your score
What is a good IQ score?
The short answer is that "good" is a comparison, not a quality. IQ scores are built so that the average is 100 by definition, and every other number simply describes how far above or below that average a result sits. Understanding how the scale is constructed tells you more than any single figure will.
The scale
Why the average is exactly 100
IQ is a relative scale, not a count of anything.
A raw test score — how many items you answered correctly — means nothing on its own, because it depends entirely on how hard the items were. To make scores comparable, raw performance is placed on a distribution that is defined to have a mean of 100 and a standard deviation of 15. This is called the deviation IQ scale.
So 100 is not a measurement of anything absolute; it is the middle of the comparison group. A score of 115 means roughly one standard deviation above that middle, and 85 means roughly one below. If the comparison group changes, the same reasoning ability can produce a different number.
The bands
Score bands and what share of people fall in them
These proportions follow from the normal distribution the scale is built on, so they are properties of the scale itself.
| Score | Share of people | In scale terms |
|---|---|---|
| 130 and above | Top ~2% | Two standard deviations above the mean. |
| 115 – 129 | Top ~16% | One to two standard deviations above. |
| 85 – 114 | Middle ~68% | Within one standard deviation of the mean. |
| 70 – 84 | Bottom ~16% | One to two standard deviations below. |
| Below 70 | Bottom ~2% | Two standard deviations below the mean. |
Note how wide the middle band is. Roughly two people in three score between 85 and 114, which means most differences people worry about are differences within the ordinary range.
Precision
Why a single number is misleading
Every test score carries measurement error, and reporting one number hides it.
Take the same test twice and you will not get the same score. The spread of those hypothetical repeat results is the measurement error, and it is why a responsible report gives an interval: a result of 108–122 says the evidence supports anywhere in that band, while "115" quietly claims a precision the test does not have.
Interval width depends on how much information the test collected. Sixteen questions give a wide band; forty-eight adaptive questions give a narrower one. This is also why comparing your number against a friend's is usually meaningless — if two intervals overlap, the test cannot tell you who scored higher.
Perspective
What a score does not tell you
An IQ estimate describes performance on a particular set of reasoning tasks under particular conditions. It says nothing about your judgement, curiosity, persistence, creativity, skill, kindness, or how well you will do at anything specific in your life. Plenty of things that matter more than reasoning speed are simply not on the test.
It also is not fixed in the way people assume. Scores move with sleep, stress, illness, mood, practice with the format and motivation on the day. That variability is one of the reasons we report a range.
And no online estimate, including ours, is a clinical or official assessment. It should not be used for diagnosis or for educational, employment or legal decisions. Our accuracy and limits page sets out exactly where the boundaries are.
Keep reading
- IQ test: how scoring worksThe deviation scale, item scoring, and why the result is a range.
- Free IQ testA 16-question test with an honest score range, no account needed.
- Online IQ test: what to expectHow online testing differs from a supervised clinical assessment.
- Abstract reasoning testRule-finding puzzles with no words or numbers involved.
- Verbal reasoning testAnalogies and relationships between words and ideas.
- Matrix reasoning testPractice the grid-pattern items used on most modern tests.
- Average IQ scoreWhy 100 is the middle of the scale and how national averages work.
- IQ score range chartFrom below average to genius, with percentiles for each band.
- IQ percentile calculatorEnter a score and see its percentile on the deviation IQ scale.
See your own range
Sixteen free questions, about eight minutes, and a score range with your percentile at the end.
Start the free testNo card required. No email needed to see your first score.