What is the highest IQ?

The scoring of modern IQ tests such as the Wechsler Adult Intelligence Scale is based on a projection of the subject's measured rank on the Gaussian bell curve with a center value (average IQ) of 100, and a standard deviation of 15. The Stanford-Binet IQ test has a standard deviation of 16.[1]

The ceiling of most standardized intelligence tests is at around the 99.9th percentile. On a sd15 test, this is at 146. For a sd16 test, this is at 149. Higher measurable scores are extremely unlikely, though the reference mentions scores as high as 190 on an sd15 test, and 196 on an sd16 test.[2]

There are 8 Schoolboys (originally reported on 21 September 2010) at Kings School in Grantham, Lincolnshire, Uk, that each have scores measured by Mensa that equal Einstein and Stephen Hawking at around 160. This is measured around the highest for the UK.

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