What Is a Good IQ Score? A Complete Breakdown by Percentile

A good IQ score is generally considered to be 110 or above. That places you in roughly the top 25% of the population, meaning you’re scoring better than three out of every four people tested. Scores above 130 are classified as “Gifted” or “Very Superior” and occur in only about 2% of the population, while the statistical average is exactly 100 - by design.

But the word “good” is doing a lot of work in that question. An IQ of 120 is solidly above average in the general population, but it’s close to average for graduate students in STEM fields. This guide breaks down the full IQ percentile scale, what each range actually means, and the context you need to read a score sensibly.

How IQ scores are defined

IQ - short for intelligence quotient - is a standardised score designed so that the population average is 100 and the standard deviation is 15 points. These aren’t arbitrary numbers: they’re chosen so that IQ scores follow a normal distribution (the familiar bell curve), which makes percentile rankings mathematically clean.

The concept was introduced by German psychologist Wilhelm Stern in 1912 and later refined by David Wechsler, whose Wechsler Adult Intelligence Scale - now in its fifth edition (WAIS-5, released by Pearson in 2024) - remains the gold standard for clinical IQ assessment. The other widely used instrument is the Stanford-Binet Intelligence Scales, currently in its fifth edition.

Both tests measure a combination of verbal comprehension, visual-spatial reasoning, fluid reasoning, working memory, and processing speed - skills that together constitute what psychologists call g, or general intelligence.

The full IQ percentile breakdown

The table below shows the standard IQ classifications used in clinical psychology, along with the approximate percentage of the population that falls into each range:

A few things worth noting about the distribution:

• Half of all people fall between 90 and 110. If your score lands here, you’re statistically unremarkable - which is the norm, not a failure.
• A score of 115 puts you at roughly the 84th percentile - scoring better than 84% of the general population.
• A score of 130 puts you at the 98th percentile - the threshold Mensa uses for membership.
• Scores above 160 are statistically unreliable on most standardised IQ tests, because the sample size of people scoring that high is too small to calibrate accurately.

What counts as “good” depends on context

A raw IQ number means different things in different settings.

In the general population

A score of 110 or higher is above average, 120 is high, and 130+ is exceptional.

Among university students

The average IQ of college-bound students tends to sit around 115. Competitive university admissions correlate with higher scores, though universities don’t administer IQ tests directly - the correlation runs through SAT/ACT/GCSE-style admissions tests, which measure overlapping cognitive abilities.

Among graduate students and specific professions

Graduate students typically average between 120 and 130 depending on discipline; PhD students in STEM fields trend toward the upper end. Large-scale occupational studies have estimated median IQs of roughly 125 for engineers and scientists, 120 for physicians, 115 for teachers and nurses, and 105 for skilled trades. These are averages, not requirements.

For Mensa membership

The threshold is scoring in the top 2% on an approved test - equivalent to an IQ of 130 on the Wechsler scale or 132 on the Stanford-Binet.

If someone tells you their IQ is 105 and frames it as disappointing, it helps to know they’re scoring better than the majority of their peers.

Famous figures and their estimated IQs

Reported IQs for historical figures should be taken with significant skepticism. Most were never formally tested, and the numbers floating around are retrospective estimates made by biographers or inferred from cognitive achievements:

• Albert Einstein: commonly cited at 160–190, but never actually tested with a modern IQ test.
• Stephen Hawking: reportedly around 160, though Hawking himself said “people who boast about their IQ are losers.”
• Marilyn vos Savant: listed in the Guinness Book of World Records with an IQ of 228, though the test used is considered unreliable at extreme values.
• Terence Tao: Fields Medal winner, reportedly tested at 230 as a child.
• Richard Feynman: famously scored 125 on a school IQ test despite winning a Nobel Prize in physics - a useful reminder that IQ tests measure a specific thing, not “genius” in general.

Does IQ change over time?

Over your lifetime, your IQ is relatively stable after about age 16. Fluid intelligence (problem-solving, pattern recognition, reasoning with novel information) tends to peak in your 20s and gradually decline, while crystallised intelligence (knowledge, vocabulary, reasoning with familiar information) tends to keep improving into your 60s or 70s.

Across generations, something more interesting happens. The Flynn effect, named after researcher James Flynn, refers to the observation that average IQ scores rose by roughly 3 points per decade across the 20th century in most developed countries. A person scoring 100 on a 1950 test would score notably lower if compared to modern norms - which is why test publishers periodically re-norm their scales.

Notably, the Flynn effect has stalled or partially reversed in several countries since around 2000 - including Norway, Denmark, and the UK - which has become a subject of active research and some cultural hand-wringing.

Does a high IQ predict success?

Partially. IQ correlates with academic achievement, job performance, and income - but the correlations are moderate, not deterministic. Meta-analyses in industrial psychology typically find that general cognitive ability predicts job performance with a correlation of roughly 0.5 in complex roles and 0.3 in simpler ones.

What that means practically: a high IQ meaningfully increases your odds of certain outcomes, but plenty of people with average IQs out-earn, out-achieve, and out-create people with very high IQs. The biggest determinants of life outcomes tend to be a mix of:

• Cognitive ability - IQ, but not only IQ
• Conscientiousness - the Big Five personality trait covering diligence, organisation, and follow-through
• Emotional intelligence - interpersonal skill, self-regulation, empathy
• Opportunity - family, access, timing, luck

A famous longitudinal study - the Terman Study of the Gifted, begun in 1921 - followed roughly 1,500 children with IQs above 135 for decades. Many became successful professionals, but most did not become world-famous “geniuses.” Meanwhile, two children who reportedly missed the study’s IQ cutoff - William Shockley and Luis Alvarez - went on to win Nobel Prizes in physics.

How to find out your IQ

There are three realistic paths:

1. Clinical testing

A licensed psychologist administers the WAIS-5 or Stanford-Binet. This is the most accurate option but typically costs £400–£1,500 and takes 2–3 hours. It’s standard for learning disability assessments, school-based giftedness testing, and certain legal contexts.

2. Supervised testing for Mensa or similar societies

Mensa offers proctored tests at a modest fee; passing (top 2%) qualifies you for membership. This gives you a credential rather than a full cognitive profile.

3. Online IQ tests

Online IQ tests vary enormously in quality. Good ones are built on the same psychometric principles as clinical instruments - normal distribution, population norming, reliability analysis - and can give you a meaningful estimate of where you sit on the bell curve. They’re not a substitute for clinical assessment, but they’re far cheaper and instantly accessible.

Our own free online IQ test is designed to give you that kind of estimate, with a detailed cognitive breakdown across verbal, spatial, numerical, and memory domains, in about 30 minutes.

Frequently asked questions

The bottom line

A “good” IQ score is 110 or above by general population standards, with 120 considered high and 130+ considered gifted. But the number itself matters less than what you do with the capabilities it reflects. A 130 IQ without curiosity or effort tends to go nowhere; a 105 IQ paired with conscientiousness and drive can go a very long way.

If you’re curious where your own cognitive profile lands, a well-constructed online test can give you a solid estimate in about half an hour.