The IQ Scale: Ranges & Classifications
Standardized intelligence scores follow a Gaussian normal distribution with a mean of 100 and a standard deviation of 15. Explore every classification tier, statistical rarity, and cognitive capacity.
The Full Intelligence Spectrum
From below 70 to 145+. Hover or click any band to highlight its attributes.
The 8 Standard IQ Classification Tiers
In-depth breakdown of Wechsler standard deviation intervals and real-world problem-solving profiles:
Profoundly Gifted
Extreme intellectual outlier. Exceptional facility with complex abstract logic, multidimensional pattern recognition, and creative problem formulation.
Very Superior / Gifted
Standard admission benchmark for Mensa. Rapid synthesis of novel concepts, deep analytical acumen, and superior abstract reasoning.
Superior
Well above general population average. Excels in rigorous academic fields, complex strategic planning, and rapid data assimilation.
High Average
Solid above-average cognitive capability. Strong inductive reasoning, reliable memory recall, and capable problem-solving agility.
Average
The psychometric center representing half of all humans. Demonstrates well-rounded cognitive balance across everyday practical tasks.
Low Average
Slightly below standardized test baseline. Frequently benefits from structured repetition, focused cognitive training, and visual mnemonics.
Borderline
Demonstrates notable difficulty with complex abstract patterns. Specialized learning accommodations are often advantageous.
Extremely Low
Scores falling below 70 (more than two standard deviations below the mean) typically indicate potential intellectual support needs.
The 68–95–99.7 Empirical Rule
Because the IQ scale is grounded in standard deviations, the population distributes according to exact mathematical laws:
IQ 85 to 115
More than two-thirds of the world’s population resides within 15 points of the median. This represents typical, everyday human cognitive baseline.
IQ 70 to 130
Over 19 out of every 20 people fall within this interval. Only 2.3% score above 130, and only 2.3% score below 70.
IQ 55 to 145
Virtually the entire human population fits within this boundary. Scores exceeding 145 represent the extreme 0.1% intellectual tail.
Common Questions About the IQ Scale
What is considered a "good" IQ score on the standardized scale?
An IQ score of 100 is the exact definition of average. Psychometrically, any score between 90 and 109 is completely normal, while scores from 110 to 119 are "High Average", 120 to 129 are "Superior", and 130+ are "Very Superior" (Mensa qualification tier).
What score is required to join Mensa or other high-IQ societies?
Mensa requires a score at or above the 98th percentile on a standardized proctored IQ test. On the standard Wechsler scale (SD 15), this corresponds to an IQ of 130 or higher.
Can practicing test questions raise my score on the IQ scale?
Yes. While an individual’s fundamental genetic cognitive baseline is relatively stable, cognitive drill practice dramatically reduces test anxiety, sharpens spatial rotation intuition, and improves matrix reasoning speed, typically raising scores by 5 to 15 points.
Why do different tests report different IQ scales?
Most modern tests (Wechsler, WAIS-IV, our platform) standardize using a mean of 100 and a standard deviation (SD) of 15. The older Stanford-Binet Form L-M used an SD of 16, and the Cattell Culture Fair used an SD of 24. A score of 130 on an SD 15 test is equivalent to 132 on an SD 16 test and 148 on an SD 24 test.