The IQ Online Center
Understand IQ scores with clear percentiles, calculators and plain-language guides.
Calculators, charts and guides
Everything here helps you read a score you already have. None of it replaces a test given by a licensed psychologist.
IQ Percentile Calculator
Turn any IQ score into a percentile, z-score and “1 in N” rarity.
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↔CalculatorPercentile to IQ Calculator
Go the other way: what IQ matches the 90th, 95th or 99th percentile?
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σCalculatorIQ Score Converter
Switch between SD 15, 16, 24, z-scores, T-scores and stanines.
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÷CalculatorMental Age and Ratio IQ
Mental age ÷ chronological age × 100, with the history and limits.
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▤ChartIQ Classification Chart
Score ranges, Wechsler labels and the share of people in each band.
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±CalculatorIQ Confidence Interval
See the likely range around a score using reliability and SEM.
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?GuideWhat Is IQ?
Meaning, history, scaling, the Flynn effect and what scores can tell you.
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✎GuideHow IQ Tests Work
Subtests, norming, reliability, and why online quizzes differ.
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!GuideIQ Myths and Facts
Ten common misunderstandings, checked against the evidence.
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No match. Try a word like percentile, ratio or myths.
What an online IQ tool can and cannot do
It can explain
Convert a score you already have into a percentile, band or another scale, using the normal curve.
It cannot diagnose
A real IQ score comes from a standardized test given by a licensed professional. Labels like “extremely high” describe position, not ability or worth.
It has a margin
Even professional scores carry roughly 3 to 5 points of error, and extreme scores are the least certain.
Quick answers
What is IQ?
IQ, or intelligence quotient, is a standardized score scaled so the average is 100. Most modern tests use a standard deviation of 15, so about two thirds of people score between 85 and 115.
What is a good IQ score?
Scores between 90 and 109 are classed as average on Wechsler scales and include about half of people. Whether a score is “good” depends on the purpose, not on the number.
Are online IQ tests accurate?
Most are not standardized or normed, so they are entertainment. Real scores come from supervised tests given by a psychologist.
What percentile is an IQ of 130?
About the 97.7th percentile on an SD 15 scale, roughly 1 person in 44 scoring higher.
Can these tools tell me my IQ?
No. They convert and explain scores you already have. They are not intelligence tests and make no diagnosis or giftedness claim.
- Intelligence quotient (Wikipedia)
- IQ classification (Wikipedia)
- Flynn effect (Wikipedia)
- Intelligence: Knowns and Unknowns (Wikipedia)
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