IQ percentile calculator
Convert an IQ score to a percentile—or a percentile to an IQ score.
84.13 percentile
- Below this score
- 84.13%
- At or above
- 15.87%
- Distance from average
- 1 SD
Calculated from a normal model, not a measured rank among starp test takers.
How the calculation works
Subtract 100 from the IQ score and divide by the selected standard deviation. The cumulative normal distribution gives the share below that position. With SD 15, IQ 115 is one standard deviation above the mean and corresponds to percentile 84.13.
For a reverse lookup, the tool finds the normal-distribution position for the percentile, multiplies it by the standard deviation, and adds 100. Percentile 98 corresponds to about IQ 130.81 with SD 15. Results are rounded for display; calculations use unrounded values.
Use the right scale
The default is mean 100 and standard deviation 15. Scale settings also allow SD 16 or 24. These are mathematical conversions; they do not equate different tests or validate an online score.
A percentile calculator does not administer an IQ test. Formal admissions depend on the accepted test and documented result; a calculated percentile alone is not qualifying evidence.
Mensa's testing guidance explains why accepted tests and their percentile standards matter.
Common reference scores
The second number is the reference percentile, using SD 15.
Browse every score from 70 to 160 · Compare two scores · Read about percentiles
Method: NIST's normal-distribution formula. Percentiles here are calculated reference values, not observed starp population ranks. About starp scoring.