IQ Percentile Calculator
Enter your IQ score and scale — get your percentile, rarity, and bell curve position instantly.
IQ Score to Percentile
Convert any IQ score to a percentile rank and population rarity
Percentile
—
out of 100
Rarity
—
people
Z-Score
—
standard deviations
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Bell Curve Distribution
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IQ Score Percentile Reference Table (Standard Scale, SD=15)
| IQ Score | Percentile | Rarity | Classification |
|---|---|---|---|
| 85 | 16th | 1 in 6 | Low Average |
| 100 | 50th | 1 in 2 | Average |
| 115 | 84th | 1 in 6 | High Average |
| 120 | 91st | 1 in 11 | Superior |
| 130 | 97.7th | 1 in 44 | Very Superior |
| 140 | 99.6th | 1 in 261 | Gifted |
| 145 | 99.87th | 1 in 741 | Gifted |
| 150 | 99.96th | 1 in 2,330 | Profoundly Gifted |
| 160 | 99.997th | 1 in 31,560 | Exceptionally Gifted |
What is the IQ Percentile Calculator?
The IQ Percentile Calculator converts any IQ score into a meaningful percentile rank and population rarity estimate. IQ scores are distributed across the population according to the bell-shaped normal distribution, with most people clustered around the mean of 100. A percentile tells you what fraction of the general population scored at or below your level — so a score at the 84th percentile means you scored higher than 84% of test-takers.
The most widely used IQ tests — including the Wechsler Adult Intelligence Scale (WAIS) and the Stanford-Binet — use a mean of 100 and a standard deviation of 15. Our calculator also supports the Cattell scale (SD=24) and the Stanine scale used in many school settings, so you can get accurate results no matter which test you took.
How to Use This Calculator
- 1 Enter your IQ score in the input field. Valid range is 1–200 (most real-world scores fall between 55 and 160).
- 2 Select your IQ scale from the dropdown. Choose Standard (SD=15) for Wechsler or Stanford-Binet results, Cattell (SD=24) for Cattell tests, or Stanine for school assessments.
- 3 Click "Calculate Percentile" to see your percentile rank, population rarity, Z-score, classification label, and an interactive bell curve showing exactly where your score falls.
IQ Score Scales Explained
Standard Scale
Mean 100 · SD 15
Used by Wechsler (WAIS, WISC) and Stanford-Binet tests. By far the most common scale worldwide. One SD above average is IQ 115; two SDs above is IQ 130.
Cattell Scale
Mean 100 · SD 24
Used by Cattell Culture Fair Intelligence Tests. A wider spread means "gifted" begins at IQ 148 on this scale, equivalent to 130 on the Standard scale.
Stanine Scale
Mean 5 · SD 2
A 9-point scale (1–9) used in many educational settings. A stanine of 7 or above generally indicates above-average performance.
The Bell Curve and IQ Distribution
IQ scores follow the normal distribution — the iconic bell-shaped curve — by deliberate test design. The curve is symmetric around the mean of 100. Approximately 68% of the population falls within one standard deviation of the mean (IQ 85–115 on the Standard scale), and roughly 95% falls within two standard deviations (IQ 70–130). The tails of the distribution represent extremely rare scores: only about 2.3% of people score above 130, and roughly 0.13% score above 145.
The bell curve visualization in the calculator above shows a vertical marker at your IQ score's position, with the shaded area to the left representing the percentage of the population you scored higher than.
IQ Classification Table (Standard Scale, SD=15)
| IQ Range | Classification | Approx. Percentile | % of Population |
|---|---|---|---|
| 130+ | Very Superior / Gifted | 97.7th+ | ~2.3% |
| 120–129 | Superior | 91st–97th | ~6.7% |
| 110–119 | High Average | 75th–91st | ~16.1% |
| 90–109 | Average | 25th–75th | ~50% |
| 80–89 | Low Average | 9th–25th | ~16.1% |
| 70–79 | Borderline | 2nd–9th | ~6.7% |
| 55–69 | Intellectual Disability (Mild) | 0.1st–2nd | ~2.2% |
| <55 | Intellectual Disability (Moderate/Severe) | <0.1st | ~0.1% |
Practical Examples
Example 1: IQ 120 on the Standard Scale
Z-score = (120 − 100) / 15 = 1.33. Percentile = normalCDF(1.33) ≈ 90.8th. Rarity = 1 in approximately 11 people. Classification: Superior.
Example 2: IQ 130 on the Standard Scale
Z-score = (130 − 100) / 15 = 2.00. Percentile ≈ 97.7th. Rarity = 1 in 44 people. Classification: Very Superior / Gifted.
Example 3: IQ 148 on the Cattell Scale (SD=24)
Z-score = (148 − 100) / 24 = 2.00. Percentile ≈ 97.7th — the same percentile as IQ 130 on the Standard scale. This shows why you must select the correct scale for meaningful results.
Frequently Asked Questions
What does IQ percentile mean?
An IQ percentile tells you what percentage of the general population scored at or below your IQ score. For example, the 97.7th percentile means you scored higher than 97.7% of people who took the same test. It is a more intuitive measure than the raw IQ number because it directly describes your relative standing in the population.
What is the average IQ score?
The average IQ score is exactly 100 by design on both the Standard (SD=15) and Cattell (SD=24) scales. IQ tests are periodically re-normed to maintain this mean. On the Stanine scale, the average is 5. A score of 100 corresponds to the 50th percentile — exactly in the middle of the population distribution.
What IQ score is considered gifted?
On the Standard scale (SD=15), an IQ of 130 or above is generally classified as Very Superior or Gifted, placing a person at roughly the 97.7th percentile. Many gifted education programs use a threshold of 130–132. Organizations like Mensa require a score in the top 2%, which corresponds to approximately IQ 130 on the Standard scale.
Is IQ fixed or can it change?
IQ scores can change somewhat, particularly during childhood, adolescence, and early adulthood. Environmental factors such as quality of education, nutrition, and stimulating experiences can influence scores. That said, relative ranking within a peer group tends to stay fairly stable for most adults. Specific test-taking practice can also raise scores, which is why a score from a properly administered standardized test is more reliable than an online quiz.
Which IQ scale should I use?
Use the Standard scale (SD=15) if your score came from a Wechsler test (WAIS, WISC, WPPSI) or a Stanford-Binet test — this covers the vast majority of professionally administered IQ tests. Use the Cattell scale (SD=24) only if you specifically took a Cattell Culture Fair test. Use the Stanine scale if your school issued a stanine score (a number from 1–9). When in doubt, Standard (SD=15) is the correct default.