An IQ of 100 is the 50th percentile by design, not by discovery. Here is why the number is set rather than measured, what the average range actually covers, and why 100 today is harder to reach than it was in 1950.
An IQ of 140 sits near the 99.6th percentile, about 1 person in 261. Here is where the genius label came from, what the research on high scorers actually found, and why the number gets unreliable this far out.
An IQ of 130 sits at the 98th percentile and is the standard gifted threshold. Here is what that number opens, what it predicts, and why the scale it came from matters more than the digits.
An IQ of 120 sits at roughly the 91st percentile, or the top 9 percent. Here is what that number actually means, what it predicts, and why the label matters less than most people think.
The Mensa IQ test guide: the 98th-percentile qualifying threshold, matching scores across scales, why online tests can’t qualify you, how to take the official test, and whether membership is worth it.
15 free practice IQ questions across abstract, verbal, numerical, and spatial reasoning, each with a full worked answer explaining the pattern, not just the correct choice.
Can you improve your IQ? What the evidence shows about education, exercise, sleep, and skill-building, what doesn’t work despite the marketing, and realistic gains to expect.
Are online IQ tests accurate? An honest look at ICAR validation data, the difference between accuracy, reliability, and validity, and how to spot a credible test from a flattering one.
How IQ tests work, from Alfred Binet’s 1905 original to modern item banks: the four cognitive domains, how raw answers become a score, and what the g-factor actually means.
The complete IQ score chart: every WAIS-IV band from below 70 to 130+, matching percentiles, the bell curve, and how Wechsler, Stanford-Binet, and Cattell scales compare.
