What Is an IQ Test and How Is IQ Measured?

An IQ test is a standardized way to estimate how well you reason compared with other people your age. It does not count how much you know — it samples problem-solving ability, then expresses your result on a scale where the average is set to 100. This article explains what an IQ test is built to measure, and how a handful of answers becomes a single number.

The idea sounds simple, but the word "measure" hides two distinct steps: first capturing your performance, then translating it into a score that means something. Understanding both is the key to reading any IQ result sensibly.

What an IQ test is trying to capture

Most IQ tests are designed to tap what psychologists call general intelligence, often written as the g factor — a broad reasoning ability that shows up across many different kinds of problems. Some tests get at it through abstract, non-verbal puzzles like Raven's Progressive Matrices; fuller batteries such as the Wechsler scales also sample verbal comprehension, working memory and processing speed, then combine them.

What a test does not measure is just as important. A score says little about creativity, acquired knowledge, motivation, practical skill or emotional understanding — a limit emphasized in the American Psychological Association's review "Intelligence: Knowns and Unknowns" (Neisser et al., 1996). For the difference between reasoning and emotional skill, see IQ vs EQ.

From raw score to IQ: how the number is made

Measuring IQ happens in two stages:

1. You take a standardized test. Everyone faces the same items, instructions and time limit, so results can be compared fairly. Counting your correct answers gives a raw score.
2. The raw score is normed. Your raw score is compared with a large, representative reference sample — ideally people your own age — and converted onto the IQ scale, where the population average is defined as 100.

This is why an IQ is a relative figure. It does not mean "you got 100 questions right"; it means "you scored higher than about half of people in your comparison group." Because reasoning performance changes across the lifespan, scores are age-normed — a point we explore in does IQ change with age.

What makes a test trustworthy

Specialists judge a test by a few core properties, and they apply just as much to a good online test as to a paper one:

• Standardization — identical conditions for everyone, so scores are comparable.
• Norming — a representative, ideally age-matched reference sample.
• Reliability — consistent results on retesting and across items.
• Validity — evidence the score really relates to the reasoning it claims to measure.

Where your result lands on the scale is easier to interpret once you know how the scale is divided; we lay that out in the IQ scale explained, and the distribution behind it in the IQ bell curve.

How our test works

The test on this site uses the matrix-reasoning format Raven popularized: 60 timed, non-verbal items of increasing difficulty, with your raw score converted to an IQ estimate using age-normed tables. By design that focuses on fluid reasoning with minimal dependence on language or schooling.

To keep expectations honest: this is an online self-assessment for educational and entertainment purposes. It is not a clinical or diagnostic instrument and is not affiliated with Mensa. We discuss the limits of unsupervised testing in how accurate online IQ tests are. The clearest way to see how it works is to take the test.