How the IQ scale turns rank into points
An IQ scale turns rank into points by showing where a test result sits among scores in a comparison group. Modern Wechsler scores use a mean of 100 and a standard deviation of 15.
The mean is the center of the scale, and the standard deviation describes how far scores tend to spread around it. A score of 100 is the center point; higher or lower scores mark positions above or below that center. The scale is designed to express relative standing, not a count of correct answers.
A result summarizes performance on that test under its norms and testing conditions. It does not describe every skill or predict every part of a person's life. To compare results, first check whether they come from the same kind of scale.
What the common IQ score bands mean
Common IQ bands group nearby scores under labels and show the share of people in each range. The nonprofit that lists the commonly used WISC-V labels notes that the labels are not the publisher's own table.
Extremely High covers 130 and above, or 2.5 percent of people. Very High covers 120 to 129, or 7.2 percent. High Average covers 110 to 119, or 16.6 percent. Average covers 90 to 109, or 49.5 percent.
Low Average covers 80 to 89, or 15.6 percent. Very Low covers 70 to 79, or 6.5 percent. Extremely Low covers 69 and below, or 2.1 percent. A band is a range, so two people with different scores can share the same label.
How to read the score bands and their shares
A band share tells you how much of the reference group falls within that range. The listed ranges partition scores into categories, so the share for a band is not the same as the share at or below its boundary.
The pattern of shares reflects a bell-shaped score curve: ranges near the center contain a larger share, while ranges farther from the center contain smaller shares. The Average range contains 49.5 percent, while the two outermost bands together contain 4.6 percent. These figures describe the listed distribution, not the odds of any particular result for an individual.
For a single score, a percentile answers a different question: what share of the reference group scored at or below that point. Use the IQ percentile calculator to understand that comparison. A band label alone does not give the exact percentile within the band.
Why the same rank can have different IQ numbers
The same relative position can receive different point values when scales use different standard deviations. Older Stanford-Binet editions report scores with SD 16. Mensa's own page says SDs of 16 or 24 points are used and gives a Cattell-scale qualifying score of 148, which fits SD 24.
One standard deviation above the mean is percentile 84.1: that position is 115 on SD 15, 116 on SD 16, and 124 on SD 24. Two standard deviations above is percentile 97.7: the scores are 130, 132, and 148, respectively. Three standard deviations above is percentile 99.87: the scores are 145, 148, and 172.
The percentile stays the same across these examples, but the point values change because each scale uses a different spread. When reading a score report, look for the test and its standard deviation. The IQ standard deviation page explains how the spread changes score values.
What IQ labels can and cannot tell you
IQ labels identify score ranges within a classification system. They do not explain why a result occurred or define a person. A label such as Low Average or Extremely High is descriptive, not a diagnosis.
A timed reasoning exercise can offer practice, but it is not the same as a normed IQ test. IQClock's free test does not print an IQ number. Its result should not be treated as an IQ score or compared with the bands on this page.