IQ Percentile and Rarity Chart

These are IQs, their percentiles, and rarity on a 15 SD (e.g. Wechsler) and 16 SD (e.g. Stanford-Binet) scale. They were calculated using the NORMDIST function in Excel. The number of decimal places for the rarity was varied in the hope it might be useful. You can see why presently nobody should be able to get a deviation IQ higher than 195 (or 201 on the 16 SD scale). There are not enough people in the world to 'beat'. Note that rarities given are of people that have a certain IQ or higher. Some people might find it more useful to know the rarity of people that have a certain IQ or lower. In that case use this example as a guide: If you want to know how many people have IQs of 84 or lower, look at the rarity of people that have an IQ of 116 or higher. (100 - 84 = 16. 100 + 16 = 116).