Guide
How to read an IQ score
An IQ result looks like one number, but a careful report gives you five things: the score, the range around it, the percentile, the classification label and the scale. Each answers a different question. Read together, they tell you far more than the headline number does alone.
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An example result
Suppose a report says your IQ is 112. Here is what each part of a careful result would tell you about that number.
| Point score | 112 |
| Range (about plus or minus 5) | 107 to 117 |
| Percentile | 78.8 |
| Classification (WAIS-IV) | High Average |
| Scale | Mean 100, standard deviation 15 |
1. The point score
The number itself is a deviation IQ: your performance compared with a reference sample of people your own age, placed on a scale where that group averages 100 and the standard deviation is 15 (Wikipedia: Intelligence quotient). A score of 112 sits 0.80 standard deviations above the mean. It is not a count of right answers and not a percentage; see is an IQ score a percentage.
The point score is the single best estimate the test can give. That is all it is. If you remember one thing from this guide, remember that the next part matters as much as this one.
Try one · Abstract Reasoning
Which tile completes the grid?
Tap the option you think is right, or show the answer.
Show the answer
The missing tile has two solid stars (option 1).
How to solve it
- Start with the first column and name what changes from tile to tile.
- Every row and every column contains each shape (square, star and triangle) exactly once.
- Every row and every column contains each number of shapes (two, one and three) exactly once.
- The fill (solid) stays the same in every tile.
- Check the rules on the second column, then apply them to the third.
- So the missing tile has two solid stars.
That was 1 puzzle. The full test has 25.
2. The confidence range
No test measures perfectly. Clinical test manuals report a confidence interval, often around plus or minus 5 points at 95%, rather than a single exact value (Wechsler, 2008). So a clinical 112 is better read as roughly 107 to 117. Shorter tests have wider ranges, because each item carries more weight.
The range changes how you should compare scores. Two results a few points apart usually overlap, which means the test cannot tell them apart. A difference only starts to mean something when the ranges barely touch. If a test shows you a number with no range at all, it is hiding its uncertainty, not removing it. Read how accurate is an IQ score for more.
3. The percentile
The percentile answers the question most people actually have: how do I compare? It is the share of people your age expected to score below you. An IQ of 112 is at about the 78.8th percentile, so it is higher than about 78.8% of people. About 1 in 5 people score 112 or higher.
Percentiles stretch and squeeze along the scale. Near the middle, a few IQ points move the percentile a lot, because most people are there: about 68% of people score between 85 and 115 (the 68-95-99.7 rule). In the tails, the same few points barely move it. That is why a jump from 100 to 110 looks large in percentile terms and a jump from 140 to 150 looks small, even though both are 10 points. Convert any score with the IQ percentile calculator.
4. The classification label
Reports often add a word. The WAIS-IV uses seven: Extremely Low (69 and below), Borderline (70 to 79), Low Average (80 to 89), Average (90 to 109), High Average (110 to 119), Superior (120 to 129) and Very Superior (130 and above) (Wikipedia: IQ classification). 112 falls in High Average.
A label is shorthand for a band. It is handy for describing a range in words, and misleading if you treat the edges as meaningful. A 109 and a 110 get different labels but, given the confidence range, are the same result. The guide to IQ classification lists all seven bands with the share of people in each.
5. The scale
Not every test uses a standard deviation of 15. Older Stanford-Binet forms used 16, and the Cattell Culture Fair III scale uses 24 (Wikipedia: IQ classification). The same percentile as 112 on a standard deviation 15 test would read as about 113 on the first and 119 on the second. A score without its scale is like a temperature without Fahrenheit or Celsius. Before comparing two results, check that they are on the same scale, or compare percentiles instead. The percentile to IQ converter handles all three scales.
Putting it together
Read the example this way: “My best estimate is 112, probably somewhere between 107 and 117. That is higher than roughly 79% of people my age, in the band the WAIS-IV calls High Average, on the standard scale.” That sentence is accurate, honest about error and easy to compare with other results.
Two last cautions. A score describes performance on one kind of test on one day; it does not describe your knowledge, skills or character. And an online estimate, including IQ Octopus, is not a clinical result. It cannot be used for Mensa admission, school placement or a diagnosis. For what a particular number means, every score from 55 to 160 has its own page, starting from the IQ score chart.
Sources
- Intelligence quotient. Wikipedia. en.wikipedia.org/wiki/Intelligence_quotient
- Wechsler, D. (2008). WAIS-IV Technical and Interpretive Manual. Pearson.
- IQ classification. Wikipedia. en.wikipedia.org/wiki/IQ_classification
- 68-95-99.7 rule. Wikipedia. en.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule