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Convert IQ scores to percentile rankings and classifications
Standard IQ tests range from 40 to 160
0.0th
Higher than 0.0% of population
IQ Score: 100
Relative standing
| IQ Range | Classification | Percentile | Percentage of Population |
|---|---|---|---|
| 145+ | Very Superior | 99.9th | 0.1% (1 in 1000) |
| 130-144 | Superior | 98th-99.9th | 2.2% (1 in 50) |
| 120-129 | High Average | 91st-98th | 6.7% (1 in 15) |
| 110-119 | Above Average | 75th-91st | 16.1% (1 in 6) |
| 90-109 | Average | 25th-75th | 50% (1 in 2) |
| 80-89 | Below Average | 9th-25th | 16.1% (1 in 6) |
| 70-79 | Borderline | 2nd-9th | 6.7% (1 in 15) |
| Below 70 | Extremely Low | Below 2nd | 2.2% (1 in 50) |
An IQ percentile calculator is a statistical tool that converts intelligence quotient (IQ) scores into percentile rankings, showing where an individual stands relative to the general population. IQ tests are designed to follow a normal distribution (bell curve) with a mean of 100 and a standard deviation of 15. This means that 68% of the population scores between 85 and 115, and 95% scores between 70 and 130. The percentile rank tells you what percentage of people scored lower than a given IQ score. For example, an IQ of 130 corresponds to the 98th percentile, meaning the person scored higher than 98% of the population. IQ tests measure various cognitive abilities including logical reasoning, pattern recognition, verbal comprehension, processing speed, and working memory. The most common standardized IQ tests include the Wechsler Adult Intelligence Scale (WAIS), Stanford-Binet Intelligence Scale, and Raven's Progressive Matrices. While IQ scores can provide useful information about certain cognitive abilities, it's crucial to understand their limitations. They don't measure creativity, emotional intelligence, practical skills, motivation, or many other forms of intelligence. Cultural bias, test anxiety, education quality, and socioeconomic factors can all influence scores. IQ is not fixed and can change with education, environmental enrichment, and practice.
IQ percentiles are calculated using the normal distribution formula based on the statistical properties of IQ test scores. The process begins with understanding that IQ scores are normalized to have a mean (average) of 100 and a standard deviation of 15 in most modern tests. To convert an IQ score to a percentile, first calculate the z-score, which represents how many standard deviations the score is from the mean: z = (IQ - 100) / 15. For example, an IQ of 130 gives a z-score of (130 - 100) / 15 = 2.0. This z-score is then converted to a percentile using the cumulative distribution function of the normal distribution, which can be found in statistical tables or calculated using mathematical formulas. A z-score of 2.0 corresponds to approximately the 98th percentile. The calculation accounts for the symmetrical bell curve distribution of IQ scores in the population. Percentiles are particularly useful because they're easier to interpret than raw scores - saying someone is in the 95th percentile is more intuitive than saying they have a z-score of 1.65. It's important to note that different IQ tests may use slightly different scales (some use a standard deviation of 16 instead of 15), which can affect percentile calculations. Professional psychologists administering IQ tests will provide both the raw score and percentile ranking as part of a comprehensive cognitive assessment report.
While IQ tests measure important cognitive abilities, they have significant limitations and don't capture the full spectrum of human intelligence. Here's what IQ tests don't measure:
Howard Gardner's theory of multiple intelligences proposes at least eight different types of intelligence: linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal, and naturalistic. Traditional IQ tests primarily measure logical-mathematical and linguistic intelligence while largely ignoring the others. Success in life depends on a complex interplay of various cognitive abilities, personality traits, emotional regulation, social skills, and environmental factors - not just IQ score.
The average IQ score is 100 by definition. IQ tests are standardized so that the mean score is always 100 and the standard deviation is 15. About 68% of the population scores between 85 and 115, which is considered the average range.
An IQ of 140 or above is often considered genius level, placing someone in the top 0.4% of the population (99.6th percentile). However, "genius" is subjective and typically requires exceptional achievement in addition to high IQ. Mensa accepts members with IQ scores in the top 2% (130+).
Yes, IQ scores can change, especially during childhood and adolescence as the brain develops. Education, environmental enrichment, nutrition, and practice can increase scores. However, adult IQ tends to be relatively stable, though it can decline with age-related cognitive changes or increase with continued mental stimulation.
Most free online IQ tests are not scientifically validated and should not be trusted. Legitimate IQ testing requires professionally administered, standardized tests like the WAIS or Stanford-Binet, given by trained psychologists in controlled conditions. Online tests often inflate scores and lack proper norming.
IQ correlates moderately with academic and career success, but it's far from the only factor. Emotional intelligence, creativity, perseverance, social skills, opportunity, and luck all play significant roles. Many successful people don't have exceptionally high IQs, while some high-IQ individuals underachieve.
The Flynn Effect refers to the observed rise in average IQ scores over generations, approximately 3 points per decade. This is likely due to improved nutrition, education, health care, and test-taking familiarity rather than actual increases in innate intelligence. IQ tests are periodically renormed to maintain a mean of 100.
Traditional IQ tests have faced criticism for cultural bias, as they may favor individuals from certain cultural and educational backgrounds. Modern tests attempt to reduce bias through culture-fair items (like Raven's Matrices), but complete elimination of cultural influence is challenging. Test results should always be interpreted with cultural context in mind.
Research suggests that while you can improve performance on IQ tests through practice and education (especially in childhood), dramatically increasing fundamental cognitive capacity is difficult. However, you can enhance specific cognitive skills through targeted training, maintain cognitive function through healthy lifestyle choices, and develop other forms of intelligence not measured by IQ tests.
This calculator is for educational purposes only. IQ scores should only be interpreted by qualified professionals such as psychologists or educational specialists. IQ is one limited measure of cognitive ability and does not define a person's worth, potential, or capabilities. Professional IQ testing requires standardized administration in controlled settings. Never make important educational or clinical decisions based solely on online calculators or unofficial test results.