Quick Reference: IQ Score by Age Group
IQ tests are age-normalised — a score of 100 represents the population average at every age, from 8 to 80. The tables below show what each score range means and how the underlying cognitive abilities change across your lifetime.
| IQ Score | Classification | Population | What it means |
|---|---|---|---|
| 130 + | Very Superior | ~2% | Significantly above average; Mensa threshold is 132 |
| 120 – 129 | Superior | ~7% | Well above average; top decile of the population |
| 110 – 119 | High Average | ~16% | Above average; typical of university graduates |
| 90 – 109 | Average | ~50% | The "normal" range; encompasses the majority of the population |
| 80 – 89 | Low Average | ~16% | Below average but within the normal range |
| 70 – 79 | Borderline | ~7% | Below average; potential need for additional learning support |
These classifications apply at every age — a child of 10 and an adult of 40 with a score of 115 are both in the "High Average" band for their respective age groups.
| Age band | Fluid intelligence | Crystallised intelligence | Processing speed |
|---|---|---|---|
| 7 – 12 | Rapid growth | Building fast | Developing |
| 13 – 17 | Strong growth | Strong growth | Increasing |
| 18 – 25 | Peak | Continuing growth | Peak |
| 26 – 40 | Gradual decline | Still growing | Slight decline |
| 41 – 60 | Moderate decline | Peak / plateau | Moderate decline |
| 61 – 70 | Steeper decline | Gradual decline | Steeper decline |
| 70+ | Significant decline | Moderate decline | Significant decline |
The Misunderstood Stability of IQ Scores
IQ scores are designed to be age-stable by construction — a score of 110 at age 25 and a score of 110 at age 55 both mean "top 25% of your age group." This statistical stability masks something more interesting: the underlying cognitive abilities that produce IQ scores change substantially across a lifetime, and they do not all change in the same direction.
Understanding how cognition actually changes with age — not just how IQ scores are normalised — has practical value for everyone thinking about their cognitive trajectory.
Childhood: Rapid Development
Cognitive development in childhood is rapid, uneven, and partially predictable. General intelligence becomes measurably stable and predictable around age 7–10, though with meaningful fluctuations for individual children. Early childhood IQ scores (before age 5) have limited predictive validity — the variance in developmental trajectories is too high.
From approximately age 7 through adolescence, fluid intelligence grows rapidly. Working memory capacity expands, processing speed increases, and the ability to handle complex multi-step reasoning develops. These gains are driven by myelination (insulation of neural pathways, increasing conduction speed) and synaptic pruning (eliminating unused connections, sharpening those that remain).
What Is a Normal IQ Score for a Child?
One of the most common questions parents have after their child takes an IQ test is whether the score is "normal for their age." The answer is built into how IQ is calculated: because every IQ test is normed against a child's specific age group, a score of 100 is always the average — whether your child is 7, 10, or 15.
In practical terms, this means:
- A score of 90–110 is firmly within the normal range at any childhood age
- A score of 115–120 places a child in approximately the top 15–10% of their age group — a meaningful advantage for academic work
- A score of 130+ indicates giftedness by the most widely used threshold (~top 2% of peers)
- A score below 80 may warrant further evaluation and potential learning support
An important caveat: IQ scores in early childhood (before age 7–8) are less reliable predictors of adult IQ than scores taken at age 10 or older. Individual children show more developmental variation at younger ages, and a single early-childhood test score should not be treated as fixed. Repeat testing a few years later often produces meaningfully different results.
Parent tip
A child who scores 95 is not "below average" in any meaningful sense — they are solidly in the middle half of their age group. IQ score anxiety in parents often creates more harm than the score itself. The most reliable predictor of a child's long-term academic outcomes is consistent engagement with learning, not a single test number.
Young Adulthood (18–30): Peak Fluid Intelligence
The early-to-mid twenties represent the peak of fluid intelligence for most people — the highest point of raw reasoning speed, working memory capacity, and abstract problem-solving ability. Processing speed also peaks here.
This is the optimal window for learning genuinely novel cognitive skills, tackling new fields, and taking on cognitively demanding challenges that require raw reasoning capacity. The advantage is real, even if the decline that follows is gradual enough to be largely imperceptible in daily life until much later.
Midlife (30–60): Compensation and Accumulation
Fluid intelligence begins declining gradually from the late twenties and early thirties — typically by about 1% per year for processing speed, less for other fluid functions. But this is not the full story.
Crystallised intelligence continues growing across this entire period. Vocabulary expands. Domain expertise deepens. Pattern recognition within familiar domains improves through accumulated experience. The strategic processing that comes from knowing which problems are worth solving and how similar problems have been solved before provides a powerful compensatory advantage.
In many real-world cognitive tasks, people in their 40s and 50s outperform people in their 20s precisely because the task rewards accumulated knowledge and expertise more than raw speed. The decline in fluid intelligence is real; its practical significance in domains where expertise matters is often small.
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The pattern of differential decline becomes more pronounced after 60. Processing speed shows the steepest decline. Working memory capacity reduces. Episodic memory (recall of specific recent events) becomes less reliable. Fluid intelligence tasks — particularly those that are novel, speeded, or require rapid rule induction — become harder.
Crystallised intelligence, vocabulary, and world knowledge remain relatively robust until late old age — often into the 70s and 80s — before showing significant decline. This is partly why many older adults continue to perform well in familiar professional domains long after their laboratory-measured fluid intelligence has declined: they are drawing on a rich crystallised knowledge base that the laboratory tasks do not capture.
The Large Individual Variation
Age-related cognitive trajectory varies enormously between individuals. Lifestyle factors — exercise, sleep, intellectual engagement, social connection, cardiovascular health — can produce differences of 15–20 years between individuals of the same chronological age in terms of cognitive performance. The "typical" trajectory is a statistical average across large populations; your individual trajectory is substantially under your influence.
The most consistent predictors of maintaining cognitive performance into later life are the same ones that maintain it at any age: cardiovascular health, regular aerobic exercise, consistent sleep, cognitive engagement through complex work and learning, and avoidance of neurotoxins. These are not magic bullets, but they are the best available levers for controlling a trajectory that is only partly predetermined.
Frequently Asked Questions
What is the average IQ score for a child?
The average IQ score is 100 at every age, including childhood. IQ tests are designed so that the average child of any given age scores exactly 100. A score between 90 and 110 is considered the normal range and encompasses roughly half the population of any age group.
Does your IQ score change as you get older?
Your IQ score — which reflects your position relative to your age group — stays broadly stable in adulthood, because it is always benchmarked against peers your age. The underlying cognitive abilities, however, do change: fluid intelligence (novel problem-solving, working memory) peaks in your mid-twenties and gradually declines, while crystallised intelligence (accumulated knowledge, vocabulary) continues growing into your 50s and 60s.
Is a score of 120 a good IQ for a teenager?
Yes — a score of 120 places a teenager (or anyone) in the top 9% of their age group, in the "Superior" classification. It indicates strong cognitive ability well above the population average and is associated with success in demanding academic and professional fields.
At what age is IQ typically highest?
The cognitive abilities that IQ tests most heavily weight — particularly fluid intelligence and processing speed — peak in the early-to-mid twenties (roughly ages 18–25). However, crystallised intelligence (the knowledge and expertise component) continues growing well beyond this and often peaks in the 40s–50s, which is why many people perform at their best on knowledge-dependent tasks well into middle age.
What is a good IQ score for a 10-year-old?
For a 10-year-old, a score of 100 is exactly average — meaning better than 50% of other 10-year-olds. A score above 115 is above average (top 16%), and above 130 is considered gifted (top 2%). IQ tests for children this age account for developmental stage, so the score directly reflects performance relative to same-age peers, not adults.
AJ
Founder & Researcher, IQScore
AJ is an English developer and cognitive science researcher currently based in Southeast Asia. He built IQScore because most online IQ tests are broken. Most sites either inflate scores to keep people happy or bury the results behind a paywall after you've already spent 20 minutes answering questions.
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