Average IQ for children, by age

The average is the same at every age because each age has its own norms. A 7-year-old and a 12-year-old who both score 100 are both exactly typical for their age, even though the 12-year-old answers far harder questions.

The average IQ of an 8, 9, 10, 11 or 12-year-old is 100. A given score also means the same thing at every one of those ages, because each age is scored against its own peers. Here is one worked example for each age.

An IQ is not a raw score. When a test is built, the publisher gives it to a large sample of people of each age. Your raw score is then compared only with people your own age, and converted to a scale where the middle of that age group is 100 and the standard deviation is 15.

That is why a 10-year-old and an 18-year-old can both have an IQ of 100 while solving very different problems. The number tells you where someone stands among their peers, not how much they know. It also means that there is no such thing as an average IQ that rises with age.

IQ testing in children measures cognitive development relative to age-matched peers. The average IQ for children is 100 by definition, as IQ scores are normalized within each age group. However, the reliability of IQ testing increases with age, and scores before age 6 should be interpreted cautiously.

• IQ scores in children are age-normalized, meaning 100 is always average for any given age
• Test-retest reliability improves significantly after age 6
• Gifted identification typically uses a threshold of IQ 130+, though this varies by program
• Environmental factors like nutrition, education quality, and home environment significantly influence childhood IQ development
• Early reading ability, large vocabulary, and intense curiosity are common indicators of high childhood IQ
• The Flynn Effect suggests average IQ scores have been rising approximately 3 points per decade across generations

In children, fluid intelligence (pattern recognition, novel problem-solving) develops rapidly and is the primary focus of childhood IQ tests like the WISC-V. Crystallized intelligence (accumulated knowledge) is still developing and depends heavily on educational exposure.

How people this age are tested

Childhood IQ tests (WISC-V, Stanford-Binet 5) are administered individually by trained psychologists, not online. Group-administered tests in schools are screening tools, not diagnostic. Test anxiety, attention span, and rapport with the examiner can all affect results. A single test score should never be used as the sole basis for educational decisions.

The average above is a statistic, not a test. The IQ test for kids and children page explains how the LifeScore test works for this group: the same 25 puzzles for everyone, not age-normed, and honest about what the number can show. Pick the page that matches the age you have in mind.

Two tools go with this page. The average IQ by age calculator turns a score into a percentile for an age group. The mental age calculator shows the old ratio formula and why modern tests dropped it.