What Is a Good IQ Score? Ranges and Percentiles Explained

The question "what is a good IQ score?" is the most frequently asked question in intelligence testing, and the answer is more nuanced than most sources acknowledge. IQ scores follow a normal distribution with a mean of 100 and a standard deviation of 15 on the Wechsler scale (the most widely used intelligence test in clinical and educational settings). This means that roughly 68% of the population scores between 85 and 115, and approximately 95% scores between 70 and 130. A score of 100 is, by definition, average; it represents the median performance of the norming population.

But "good" is a value judgment, not a statistical one. Whether a score of 112 or 125 or 98 is "good" depends entirely on context: what you are trying to do, what doors you want the score to open, and what limitations you are willing to accept in the measurement itself. This article provides the full statistical framework, explains what each score range means in practical terms, addresses the most persistent myths, and examines the genuine limitations of IQ as a measure of human cognitive capacity.

The Standard IQ Scale

Modern IQ tests are designed so that scores form a bell curve (normal distribution) centered on 100. The standard deviation, which measures how spread out scores are from the mean, is set at 15 points on the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children (WISC). The Stanford-Binet Intelligence Scales, Fifth Edition (SB5) also uses a mean of 100 and SD of 15, though earlier versions used an SD of 16.

This standardization is not a natural phenomenon; it is a design choice. Test publishers periodically renorm their tests (typically every 15-20 years) to maintain the mean at 100. Without renorming, raw scores would drift upward over time due to the Flynn Effect, the well-documented phenomenon of rising raw IQ scores across generations.

"An IQ score is not a fixed property of a person, like height or blood type. It is a rank ordering: a statement about how a person performed relative to a specific reference population at a specific point in time." --- Alan S. Kaufman, IQ Testing 101 (2009)

IQ Score Ranges and Classifications

Different IQ tests use slightly different classification labels, but the ranges are broadly consistent. The table below uses the Wechsler classification system, which is the most widely referenced in clinical practice:

IQ Score Range Classification Percentile Range Approximate % of Population
145+ Very Superior (Profoundly Gifted) 99.9th+ 0.1%
130-144 Very Superior (Gifted) 98th-99.8th 2.1%
120-129 Superior 91st-97th 6.7%
110-119 High Average 75th-90th 16.1%
90-109 Average 25th-74th 50%
80-89 Low Average 9th-24th 16.1%
70-79 Borderline 2nd-8th 6.7%
Below 70 Extremely Low Below 2nd 2.3%

Several things to notice about this distribution. The "average" range (90-109) encompasses a full half of the population. A person scoring 91 and a person scoring 109 receive the same classification despite an 18-point gap that represents meaningful cognitive differences in certain task domains. The classification system is deliberately broad, which is appropriate for clinical purposes but frustrating for people seeking precise self-knowledge.

What the Percentiles Mean

Percentile rank tells you the percentage of the norming population that scored at or below your score. A percentile of 75 means you scored equal to or higher than 75% of people.

IQ Score Percentile Practical Meaning
70 2nd Scores below 70 may indicate intellectual disability if accompanied by adaptive functioning deficits
85 16th Lower boundary of the average range; one standard deviation below the mean
90 25th Lower quartile of the average range
100 50th Exact population mean
110 75th Upper quartile of the average range
115 84th Upper boundary of the average range; one standard deviation above the mean
120 91st Top 9% of the population
130 98th Top 2%; typical gifted classification threshold
140 99.6th Top 0.4%; approximately 1 in 260 people
145 99.9th Top 0.1%; approximately 1 in 1,000 people
160 99.997th Approximately 1 in 31,000 people

Above 145, the precision of IQ scores decreases rapidly. Tests are normed on the general population, and the number of people at extreme scores is so small that statistical confidence intervals widen substantially. A score of 160 on a Wechsler test should be interpreted with considerable caution; the test was not designed to discriminate reliably at that level.

What IQ Scores Mean Practically

Education

IQ scores correlate with academic performance at approximately r = 0.50 to 0.60, making IQ one of the strongest single predictors of educational outcomes. However, a correlation of 0.50 means IQ explains roughly 25% of the variance in academic achievement. The remaining 75% is explained by motivation, study habits, teaching quality, family support, socioeconomic status, and other factors.

Gifted education programs typically require an IQ of 130 or higher (98th percentile). Some programs use a lower threshold of 120 or 125, particularly when combined with achievement test scores or teacher recommendations. The rationale is not that children below 130 cannot excel, but that children above 130 often require qualitatively different instruction: faster pacing, more abstraction, and greater intellectual challenge.

Special education eligibility historically used an IQ below 70 as one criterion for intellectual disability diagnosis. Current diagnostic standards (DSM-5) require both low IQ scores and deficits in adaptive functioning (daily living skills, communication, social participation). An IQ score alone is neither necessary nor sufficient for any educational placement.

Career and Professional Outcomes

IQ correlates with job performance at approximately r = 0.40 to 0.55 across occupations, with stronger correlations in complex jobs (management, engineering, law, medicine) and weaker correlations in routine manual labor. Research by Schmidt and Hunter (1998), in one of the most influential meta-analyses in industrial-organizational psychology, concluded that general mental ability is the single best predictor of job performance across all job types.

However, the practical meaning of this correlation requires careful interpretation. An IQ of 115 does not guarantee professional success, and an IQ of 95 does not preclude it. In fields requiring specialized skills, domain knowledge, interpersonal ability, or physical performance, IQ's predictive power diminishes relative to other factors.

Some rough associations between IQ ranges and typical educational/professional trajectories (drawn from Gottfredson, 1997):

  • IQ 75-90: Can complete routine, well-structured tasks; may struggle with complex written instructions
  • IQ 90-104: Can complete most jobs with moderate complexity; typical for skilled trades, clerical work, sales
  • IQ 104-115: Can handle professional and technical work with training; typical for teachers, nurses, managers
  • IQ 115-130: Can master complex material independently; typical for attorneys, physicians, engineers, scientists
  • IQ 130+: Can handle the highest levels of abstract reasoning; no professional ceiling attributable to cognitive ability

These are population-level tendencies, not individual predictions. Countless exceptions exist in both directions.

"Intelligence is a rising tide that lifts all boats. It does not determine which boat wins the race." --- Linda Gottfredson, "Why g Matters," Intelligence (1997)

The Mensa Threshold and High-IQ Societies

Mensa International requires a score at or above the 98th percentile for membership, which corresponds to approximately 132 on the Wechsler scale or 132 on the Stanford-Binet 5. Mensa accepts scores from over 200 recognized IQ tests, and each test has its own qualifying score.

Other high-IQ societies set higher thresholds:

  • Intertel: 99th percentile (IQ 135+)
  • Triple Nine Society: 99.9th percentile (IQ 146+)
  • Prometheus Society: 99.997th percentile (IQ 160+)

The practical value of Mensa membership is debated. The organization provides social networking opportunities for high-IQ individuals, local chapter events, and publications. Critics argue that IQ-based social selection is a poor proxy for interesting companionship, since intelligence and social compatibility are weakly related. Supporters counter that shared intellectual curiosity creates a unique social environment unavailable in most settings.

Famous IQ Scores: Separating Fact from Fiction

The internet is saturated with claims about the IQ scores of historical figures and celebrities. Most of these claims are fabricated or extrapolated from dubious sources. Some clarifications:

Albert Einstein never took a modern IQ test. The widely cited score of 160 is a posthumous estimate by Cox (1926), who retrospectively estimated the IQs of historical figures based on biographical achievements. These estimates have large margins of error and should not be treated as measured scores.

Stephen Hawking, when asked his IQ in a 2004 interview with The New York Times, responded: "I have no idea. People who boast about their IQ are losers."

Marilyn vos Savant holds the Guinness World Record for highest recorded IQ at 228 (Mega Test, 1985). However, this score was obtained on an experimental, non-standardized test whose psychometric properties have been questioned. Her Wechsler-equivalent score would likely be considerably lower, though still exceptional.

Richard Feynman reportedly scored 125 on a school IQ test, which is above average but far below the "genius" threshold. This is frequently cited as evidence that IQ tests are poor measures of scientific ability. The more likely explanation is that his school administered a group-administered test with limited ceiling, or that Feynman's extraordinary physics ability depended on domain-specific spatial and mathematical reasoning not fully captured by a general IQ measure.

"The IQ test measures a specific set of cognitive skills. It does not measure creativity, practical intelligence, emotional regulation, or domain-specific expertise. Treating it as a comprehensive measure of human worth is both scientifically unjustified and socially harmful." --- Robert J. Sternberg, Successful Intelligence (1996)

IQ and Military Service: The ASVAB Connection

The Armed Services Vocational Aptitude Battery (ASVAB) is the military's standardized test for enlistment and job classification. The ASVAB's general score, the Armed Forces Qualification Test (AFQT), correlates highly with IQ scores (r = 0.80 to 0.85).

AFQT categories and their approximate IQ equivalents:

AFQT Category Percentile Range Approximate IQ Equivalent
I 93-99 120+
II 65-92 107-119
IIIA 50-64 100-106
IIIB 31-49 92-99
IV 10-30 81-91
V 1-9 Below 80

By federal law, the military cannot enlist anyone scoring in Category V (below the 10th percentile), and no more than 20% of enlistees in any fiscal year can come from Category IV. In practice, most branches strongly prefer Category IIIA and above. The military discovered through extensive research during the 1960s and 1970s (Project 100,000) that individuals scoring in the lowest AFQT categories experienced significantly higher rates of training failure, disciplinary problems, and early discharge.

The ASVAB also determines which Military Occupational Specialties (MOS) a recruit qualifies for. Technical roles (electronics, cryptology, intelligence analysis, nuclear engineering) require high composite scores on specific ASVAB subtests, not just high AFQT scores.

Limitations of IQ Scores

Understanding what IQ scores do not measure is as important as understanding what they do measure.

Test-Retest Variability

IQ scores are not perfectly stable. Test-retest reliability for the WAIS-IV is approximately 0.90 to 0.96, which is excellent by psychometric standards but still permits score fluctuations of 3-7 points between testing sessions. Factors that affect scores include sleep quality, anxiety, medication, illness, and familiarity with the test format.

Cultural and Linguistic Bias

IQ tests are normed on specific populations, and performance can be affected by cultural familiarity with test content and format. Non-verbal tests (like Raven's Progressive Matrices) reduce linguistic bias but do not eliminate cultural influences entirely. The experience of sitting for a timed, standardized test is itself culturally specific; populations without extensive exposure to formal testing may score lower due to unfamiliarity rather than lower cognitive ability.

The Narrow Scope of "g"

IQ tests primarily measure g (general intelligence), a statistical construct derived from the observation that performance on diverse cognitive tasks is positively correlated. Critics, including Howard Gardner (multiple intelligences theory) and Robert Sternberg (triarchic theory), argue that g captures only a subset of human cognitive abilities and excludes practically important capacities like interpersonal skill, creative thinking, bodily-kinesthetic intelligence, and practical problem-solving.

The scientific consensus acknowledges both that g is real, robust, and predictive, and that it does not capture the full range of human cognitive capacity. These positions are not contradictory.

IQ Is Not Fixed

IQ scores are moderately heritable (twin studies estimate heritability at 50-80% in adults), but heritability does not mean immutability. Environmental interventions, particularly during childhood, can substantially affect IQ scores. The Flynn Effect itself demonstrates that population-level IQ scores change in response to environmental conditions, including nutrition, education, and cognitive stimulation.

Research comparing animal cognition and human intelligence measurement reveals that even the concept of "intelligence" is not straightforward. Octopuses solve novel problems, corvids use tools, and dolphins demonstrate self-awareness, yet none of these capacities map neatly onto human IQ constructs. The lesson is that intelligence is multidimensional across species and within our own.

What Constitutes a "Good" Score

After all the statistics, the practical answer to "what is a good IQ score?" depends on your purpose:

For self-understanding: Any score provides useful information about relative cognitive strengths and weaknesses, particularly if you receive a full-scale report with subtest scores (verbal comprehension, perceptual reasoning, working memory, processing speed). The composite number is less useful than the profile.

For educational placement: Gifted programs typically require 130+. Selective schools and programs often look for 120+. Average-range scores (90-109) do not preclude academic success; they indicate that the student will benefit from standard instructional methods and pacing.

For career planning: In knowledge-intensive fields, higher IQ scores correlate with faster learning and better performance on complex tasks. For professional certification preparation, research suggests that cognitive ability predicts how quickly candidates master technical material, though study strategy and time investment remain the dominant factors in exam outcomes.

For Mensa or high-IQ society membership: You need 132+ on a Wechsler-scale test.

For bragging rights: This is the wrong framework entirely. IQ measures a narrow set of cognitive abilities. It does not measure character, creativity, wisdom, empathy, or any of the other qualities that make a person interesting, effective, or admirable.

The relationship between IQ and practical outcomes like writing ability illustrates this point well. Higher IQ correlates with better vocabulary and more complex sentence construction, but the best writers are not the highest-IQ individuals; they are the ones who combine adequate cognitive ability with extensive practice, domain knowledge, genuine curiosity, and the discipline to revise their work repeatedly.

The Score Is Not the Person

IQ testing has been one of psychology's most successful and most controversial inventions. The tests predict real-world outcomes better than virtually any other single psychological measure. They also reduce a complex, multidimensional human being to a number, which inevitably distorts more than it reveals.

If you have received an IQ score, use it as one data point among many. If it is higher than you expected, do not let it inflate your self-concept beyond what your actual accomplishments warrant. If it is lower than you expected, do not let it constrain your ambitions. The test measures a specific set of cognitive tasks administered on a specific day under specific conditions. It does not measure your potential, your value, or your capacity for growth.

The most productive relationship with your IQ score is curiosity without attachment: interested in what it reveals, undisturbed by what it does not.

References

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  2. Kaufman, A. S. (2009). IQ Testing 101. Springer Publishing Company. doi:10.1891/9780826106292

  3. Schmidt, F. L., & Hunter, J. E. (1998). The validity and utility of selection methods in personnel psychology: Practical and theoretical implications of 85 years of research findings. Psychological Bulletin, 124(2), 262-274. doi:10.1037/0033-2909.124.2.262

  4. Gottfredson, L. S. (1997). Why g matters: The complexity of everyday life. Intelligence, 24(1), 79-132. doi:10.1016/S0160-2896(97)90014-3

  5. Flynn, J. R. (2007). What Is Intelligence? Beyond the Flynn Effect. Cambridge University Press. doi:10.1017/CBO9780511605253

  6. Sternberg, R. J. (1996). Successful Intelligence: How Practical and Creative Intelligence Determine Success in Life. Simon & Schuster. ISBN: 978-0-684-81410-0

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  8. Plomin, R., & von Stumm, S. (2018). The new genetics of intelligence. Nature Reviews Genetics, 19(3), 148-159. doi:10.1038/nrg.2017.104