The complete IQ score guide
Seven IQ bands cover the entire population distribution, from extremely low (below 70) through very superior (130+). Each band has its own deep-dive page with percentile context, population frequency, real-world implications, and clinical caveats.
Extremely low
More than two standard deviations below the mean.
Roughly 2.3% of the population
Read interpretationBorderline
Below average; may indicate a need for more support on novel reasoning tasks.
Roughly 6.7% of the population
Read interpretationLow average
Below the central range, but within the broad average band on most tests.
Roughly 16% of the population
Read interpretationAverage
The middle two-thirds of the population sit in this range.
Roughly 50% of the population
Read interpretationHigh average
Above the typical range; common in graduate study and many professional fields.
Roughly 16% of the population
Read interpretationSuperior
Roughly the top decile — common in technical and research roles.
Roughly 7% of the population
Read interpretationVery superior
Two standard deviations above the mean.
Roughly 2.3% of the population
Read interpretationHow the bands are defined
Almost every modern IQ instrument calibrates to the same scale: a normal distribution with a mean of 100 and a standard deviation of 15. A score of 100 sits exactly at the population median. A score of 115 is one standard deviation above (roughly the 84th percentile). A score of 130 is two standard deviations above (roughly the 98th percentile). The same logic mirrors below the mean: 85 is the 16th percentile, and 70 is the 2nd.
The bands here use the conventional labels reported by the Wechsler Adult Intelligence Scale (WAIS-IV) and the Stanford-Binet Intelligence Scales (SB5). Other instruments use slightly different cutoffs (the Cattell scale, for example, uses an SD of 24 instead of 15) but the underlying concept is the same.