Convert an IQ score into a percentile rank based on the standard normal distribution.
How It Works
How IQ Percentile Calculator Works
IQ scores are designed to follow a normal distribution with a mean of 100 and a standard deviation of 15 — the calculator converts your score into a z-score (how many standard deviations from average it is) and then applies the standard normal distribution to find what percentage of people would be expected to score at or below that value.
Worked Example
See It In Action
An IQ of 130 is exactly 2 standard deviations above the mean, placing it at roughly the 97.7th percentile — meaning only about 2.3% of people would be expected to score higher.
FAQ
Frequently Asked Questions
Does every IQ test use the same mean and standard deviation?
Most major modern IQ tests are standardized to a mean of 100 with a standard deviation of 15, but a few older or specialized tests use a different standard deviation (like 16 or 24) — check which scale your specific test result used before comparing percentiles.
Is IQ actually normally distributed in the real population?
Test publishers deliberately calibrate scoring so that results approximate a normal distribution across a large standardization sample — it's a designed property of the test scoring, not a spontaneously occurring natural pattern.
