What Is an IQ Score? Intelligence Quotient Scores Explained
You finish a test, a number appears, and it feels strangely official — but what is that number actually counting? An IQ score is not a tally of right answers and it is not a percentage. Understanding how it is built is the difference between reading it wisely and reading too much into it.
Here is the short version. An IQ score is a standardized number that shows how your performance on a reasoning test compares with other people your age. It is not the number of questions you got right; it is your rank translated onto a scale where the average is always 100 and most people fall between 85 and 115. As of 2026, that is what every mainstream IQ score represents.
How an IQ score is calculated
This is the part that surprises people: your raw performance is only the starting point. Here is the chain from answers to score.
- You complete the test items, producing a raw score (how you did on the tasks).
- That raw score is compared against a large, representative sample of people your own age — the "norming" group.
- Your standing relative to that group is converted onto the standard IQ scale, where the average is set to 100 and the standard deviation to 15.
So an IQ score is fundamentally a comparison, not a count. Two people who answer the same number of questions could receive different IQ scores if they are different ages, because each is measured against their own age group.
| If your score is… | You are… | Percentile |
|---|---|---|
| 100 | Exactly average | 50th |
| 115 | One SD above average | ~84th |
| 130 | Two SD above average | ~98th |
| 85 | One SD below average | ~16th |
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Why the average is always 100
The scale is designed that way on purpose. Setting the mean to 100 and the standard deviation to 15 gives everyone a common reference point: any score instantly tells you how far from typical it is, and how rare it is. It also means the average never changes with age — a 100 at age 12 and a 100 at age 60 both mean "typical for your age," because each is scored against peers.
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How to read your IQ score sensibly
Three habits keep you from over-reading a score. First, treat it as a range, not a point — every score has a few points of measurement error, so a 122 and a 126 are effectively the same. Second, remember it reflects specific reasoning skills on one day, influenced by sleep, stress, and test familiarity. Third, confirm anything important with a properly administered test, since a single online result is a useful estimate but not a clinical measurement.
Read that way, an IQ score is genuinely informative: a quick, standardized snapshot of certain thinking skills. Read as a permanent verdict on your worth or potential, it claims far more than it can deliver.
What can affect your IQ score
Because a score is a snapshot, several everyday factors can nudge it up or down on a given day. Knowing them helps you interpret a result fairly rather than treating it as fixed.
- Sleep and fatigue — a tired brain reasons more slowly, which especially hits timed sections.
- Stress and anxiety — test pressure can depress performance below your true ability.
- Familiarity with the format — knowing what the questions look like removes a small learning curve; this is the "practice effect."
- Health and nutrition — general well-being on the day affects concentration.
- Test quality — a poorly designed or unnormed test can produce a misleading number in either direction.
None of these changes your underlying ability, but together they explain why the same person can score a few points differently on two occasions. It is another reason to read a score as a range, and to weight a supervised, well-constructed test far more heavily than a quick online quiz taken at midnight.
The takeaway is not to distrust IQ scores, but to hold them at the right resolution: precise enough to be useful, loose enough that a handful of points either way should not change how you see yourself. A good score is a data point that can inform how you learn and where you lean on your strengths — not a label that fixes who you are or what you can become.
Frequently Asked Questions
Q: What is a good IQ score?
A: Anything in the 90–109 range is average and perfectly good, 110–119 is above average, and 120+ is superior. About two-thirds of people score between 85 and 115.
Q: Is an IQ score the number of questions I got right?
A: No. It is a standardized comparison to others your age, not a raw count or a percentage. Your raw performance is converted onto a scale centered on 100.
Q: Why is the average IQ score 100?
A: By design. The scale is deliberately set so the average is 100 and the standard deviation is 15, giving everyone a common reference for how far from typical a score is.
Q: Can my IQ score change over time?
A: Modestly. Your underlying ability is fairly stable, but scores can shift somewhat with age, education, health, and test conditions — which is why a score is best read as an estimate.
References
- American Psychological Association — Intelligence
- Encyclopaedia Britannica — Intelligence quotient
- MedlinePlus Genetics — Intelligence
Last updated: July 13, 2026
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