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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.