Where does IQ 70 sit on the curve?
IQ 70 is two standard deviations below the mean of 100 on the Wechsler scale, which has a standard deviation of 15. About 2.3 percent of scores fall at or below 70 under this model.
On scales with different standard deviations, the same position is 68 on a scale with a standard deviation of 16, or 52 on one with a standard deviation of 24. The number depends on the scale, so scores from different tests may not be directly comparable. See the IQ standard deviation guide for how the spread affects scores.
Why is 70 not a diagnosis by itself?
A score of 70 is at a boundary between score labels: Very Low starts at 70, while Extremely Low is 69 and below in commonly used WISC-V labels listed by a nonprofit. A label describes a score range, not a diagnosis or a complete account of someone’s functioning.
One test result cannot provide enough context on its own. A qualified professional considers the result alongside other evidence and the person’s circumstances. The IQ scale guide explains why score bands are broad descriptions.
Who can give a full Wechsler test?
Only qualified examiners can buy the Wechsler tests. The publisher sells the WAIS only to users with Qualification Level C.
A timed online reasoning quiz is not a full Wechsler assessment and does not produce an IQ score. When an IQ score has practical consequences, discuss it with a qualified examiner who can choose an appropriate test and explain its limits.