IQ Percentile Calculator
Convert an IQ score to its percentile rank using the standard normal distribution (mean 100, SD 15).
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How to use this tool
- Enter the IQ score you want to look up.
- Confirm the mean and standard deviation match your test (100/15 for most modern IQ tests).
- Read the percentile rank and z-score.
IQ scores follow a normal (bell-curve) distribution with a mean of 100 and a standard deviation of 15 for most modern tests. This calculator converts any IQ score to its percentile rank — the share of the population that scores at or below it — using the standard normal distribution.
⚠ This tool provides general estimates for education only and is not financial, tax or legal advice. Figures may not reflect your situation — verify with a qualified professional.
Frequently asked questions
- What percentile is an IQ of 130?
- An IQ of 130 is 2 standard deviations above the mean (z=2), which corresponds to roughly the 97.7th percentile — about 2.3% of people score at or above it.
- Why do some sources give slightly different percentiles for the same IQ?
- Small differences come from which normal-distribution approximation is used and from real test norms deviating slightly from a perfect bell curve, especially far from the mean.