Average IQ Trends by Age
A rough guide to how average IQ, processing speed, and memory tend to change across age groups, with an explanation of the difference between fluid and crystallized intelligence.
In brief: Because IQ is standardized within each age group, the average IQ stays at 100 at every age. What changes is the mix: fluid intelligence and processing speed tend to be highest around the twenties, while crystallized intelligence keeps growing into middle age and beyond. The figures on this page are illustrative values based on established findings.
- TeensFluid 102 ／ Crystallized 92 ／ Processing speed 105
- 20sFluid 105 ／ Crystallized 98 ／ Processing speed 108
- 30sFluid 101 ／ Crystallized 103 ／ Processing speed 102
- 40sFluid 97 ／ Crystallized 106 ／ Processing speed 96
- 50sFluid 93 ／ Crystallized 108 ／ Processing speed 90
- 60s+Fluid 88 ／ Crystallized 107 ／ Processing speed 83
Fluid intelligence (the ability to solve novel problems) tends to peak at a young age, while crystallized intelligence (knowledge and vocabulary) tends to grow with age. Values are indicative trends expressed on the mean-100, SD-15 scale.
Frequently asked questions
- Does average IQ change with age?
- No. IQ is standardized to a mean of 100 within each age group, so the average stays at 100 at every age. What changes with age is the mix of abilities, such as fluid intelligence and processing speed.
- At what age does intelligence peak?
- Fluid intelligence (solving novel problems) and processing speed tend to be highest around the twenties, while crystallized intelligence (knowledge and vocabulary) tends to keep growing into the forties to sixties. The peak depends on the type of ability.
- Are the figures on this page measured data?
- No. They are illustrative trend values based on established research on age and cognition, not aggregated from actual test takers.
* Figures are estimates and illustrative values based on a normal distribution model and general findings. They are not aggregated from actual test-taker data.