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IQ Percentile Calculator

Enter an IQ-style score to estimate its percentile rank on the common 100 mean / 15 SD scale. The calculator is free, runs in your browser, and does not require login or email.

Convert IQ Score to Percentile

Use a score between 40 and 180. The formula is based on the cumulative normal distribution:

percentile = Phi((IQ - 100) / 15) * 100

Important Caveats

  • This is an educational conversion tool, not a diagnosis or professional assessment.
  • Percentiles are theoretical estimates from the standard normal model, not population norms from a supervised clinical sample.
  • Extreme-tail estimates above about IQ 145 are less stable because real tests have fewer calibration cases there.
  • No score entered here is stored, submitted, or connected to an account.

Related References

For the full lookup table and score-band context, see the IQ percentile chart and IQ score chart. To understand how What's Your IQ reports results, read the methodology page. To compute the mean and standard deviation of any set of scores, use the statistics calculator.