The most commonly used IQ rating scale as of 2014, the Stanford-Binet scale, classifies intelligence as ranging from feeble-mindedness to genius. The Wechsler scale and Cattell's scale are two other scales that are useful for quantifying intelligence, although there is some disparity among these scales.
According to the Stanford-Binet scale, a score of less than 70 indicates feeble-mindedness, a score of 70 to 79 indicates a borderline deficiency in intelligence, a score of 80 to 89 indicates dullness and a score of 90 to 109 indicates average or normal intelligence. A score of 100 is the average score. A score of 110 to 119 signifies superior intelligence, a score of 120 to 140 indicates very superior intelligence, and a score greater than 140 indicates genius or almost genius intelligence.
The Wechsler scale classifies a score of under 70 as extremely low, a score of 70 to 79 as borderline, a score of 80 to 89 as low average, a score of 90 to 109 as average, a score of 110 to 119 as high average, a score of 120 to 129 as superior and a score greater than 130 as very superior. Cattell's scale classifies a score of 90 to 99 as below average, a score of 100 to 119 as average, a score of 120 to 139 as above average, a score of 140 to 159 as highly intelligent and a score greater than 160 as genius level.