Average IQ by age

Last updated 1 August 2026

The average IQ at every age is 100. Here is the answer most pages bury: the average IQ for every age group is 100, because that is how the scale is built. But underneath that flat number, real cognitive abilities change dramatically across a lifetime — and understanding which ones rise, which fall, and when, is far more useful than any table of invented age averages.

The average IQ by age chart people are looking for

Search this phrase and you will find the same table on dozens of sites, giving a different average for each age group. Here it is, because it is what most people came for, followed by what it actually is.

Every figure in that table comes from comparing an age group against a single, all-ages reference sample. That is not what an IQ score is. A real IQ score compares you with people your own age, which is why the properly normed answer to "what is the average IQ for my age" is always the same number: 100. The table is a measure of how each age group performs on one fixed test, dressed up as intelligence.

Why the average is always 100, at every age

IQ scores are age-normed. When a test is standardised, the norming sample is split into age bands, and your raw performance is compared only with people in your own band. A 16 year old is scored against 16 year olds; a 70 year old against 70 year olds. Each band's average is then anchored to 100. The consequence is that "average IQ by age" is a flat line at 100 by definition — a 12 year old with an IQ of 110 and a 60 year old with an IQ of 110 are each one notch above their own age peers, even though their raw abilities differ enormously.

This is also why a child cannot meaningfully compare IQ scores with a parent, and why you will sometimes see tables online listing "average IQ 105 for ages 18 to 19" or similar. Those tables describe quirks of particular samples on particular tests, not properties of the scale. Any table claiming systematically different average IQs by age has misunderstood — or is misrepresenting — how norming works.

What genuinely changes with age: fluid vs crystallised ability

Psychologists split general intelligence into two broad streams, and they age in opposite directions.

Fluid intelligence: the early peak

Fluid intelligence is the raw machinery: processing speed, working memory, and the ability to spot patterns and solve novel problems with no learned knowledge to lean on. It is what matrix reasoning tests measure. Raw fluid performance rises steeply through childhood, peaks somewhere in the mid 20s, holds a high plateau, and then declines slowly and steadily from roughly the 30s onward — with processing speed falling first and most visibly. This decline is normal, universal, and gentler than most people fear: the typical drop across middle age is gradual, and large individual differences swamp the average trend.

Crystallised intelligence: the long climb

Crystallised intelligence is everything you have accumulated: vocabulary, facts, professional expertise, and the dense web of experience that lets an older head solve a familiar problem in one move where a younger one needs ten. Raw crystallised performance keeps rising through the 40s and 50s, often peaking in the 60s, and declines only late and slowly. This is why professions that lean on judgement and accumulated knowledge — law, medicine, management — routinely see people performing at their best decades after their fluid peak has passed.

The lifespan picture, decade by decade

Putting the research together, here is how raw cognitive abilities typically move across the lifespan. Remember throughout: IQ scores stay centred on 100 because each age group is compared with itself — this table describes raw ability, not scores.

Average IQ for a specific age

What is at peak for your age right now

Enter your age to see which cognitive abilities are typically climbing, peaking, or past peak for someone your age, based on peak-performance estimates from Hartshorne and Germine's analysis of 48,537 participants.

Two honest caveats about this picture. First, much of the classic data is cross-sectional — comparing today's 25 year olds with today's 65 year olds — which entangles ageing with generational effects such as education and the Flynn effect. Longitudinal studies that follow the same people over decades generally find later and gentler fluid decline than cross-sectional snapshots suggest. Second, the spread within any age group dwarfs the average change between age groups: plenty of 60 year olds out-reason plenty of 25 year olds on fully novel problems.

At what age does IQ peak?

There is no single peak. Different cognitive abilities peak at different ages, spread across roughly five decades, which is why the question has no one-number answer. Hartshorne and Germine's analysis of 48,537 participants put the peaks at approximately these ages.

If you want one answer: raw fluid reasoning, the kind a matrix test measures, peaks in the mid twenties. Overall measured IQ does not peak at all, because it is re-centred on 100 for every age band. Someone at 65 with a vocabulary at its lifetime maximum and processing speed well past its own is scored against other 65 year olds, and the two effects wash out.

The Flynn effect: why generations cannot be compared

Across the twentieth century, raw IQ test performance rose steadily in country after country — roughly three points per decade — a phenomenon named the Flynn effect after James Flynn's 1987 analysis of 14 nations. Better nutrition, more schooling, smaller families, and increasingly abstract daily environments all likely contributed. Test publishers responded by periodically re-norming, resetting each new generation's average back to 100. The practical consequence: an IQ of 100 today reflects a higher raw performance than an IQ of 100 in 1950, and comparing scores across generations — or across old and new versions of a test — is meaningless without adjustment. In several developed countries the effect has plateaued or slightly reversed since the 1990s, for reasons still actively debated.

Can you protect fluid ability as you age?

The evidence-backed levers are unglamorous. Physical exercise, particularly aerobic, has the strongest and most consistent association with maintained cognitive performance in later life. Managing cardiovascular health — blood pressure, diabetes, smoking — matters because the brain runs on the vascular system. Sleep, social engagement, and continued learning of genuinely new skills all show protective associations. Commercial brain-training games, by contrast, mostly make you better at the games: transfer to broader ability has repeatedly failed to appear in well-controlled studies. If you want one rule, it is that what is good for the heart is good for the head.

Four myths about age and intelligence

"You lose brain cells every day after 30." Large-scale neuron loss in healthy ageing is a myth; what changes is processing speed and some connectivity, and the brain compensates by recruiting more regions for the same task — older adults literally solve problems with different neural strategies, often just as successfully.

"You can't learn new things past a certain age." Learning slows; it does not stop. Adults acquire new languages, instruments, and professions at every age. The realistic difference is that a 60 year old typically needs more repetitions than a 20 year old to cement the same novel material — a cost worth knowing about and planning around, not a wall.

"Doing puzzles keeps your whole mind young." Practice effects are narrow. Crosswords make you better at crosswords. What shows broad protective associations in the research is physical exercise, social engagement, and managing cardiovascular risk — the boring trinity beats the puzzle book.

"Cognitive decline is inevitable and uniform." The variance between individuals dwarfs the average trend at every age. Substantial numbers of people in their 70s perform within the range typical of the middle-aged, and the factors that predict who — education, health, activity — are partly modifiable. The average curve is real; nobody is obliged to sit on it.

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