Rare in a concrete, everyday way
About six times rarer than Mensa's 130, yet nowhere near the 1-in-30,000 scores out at 160. Common enough to find peers, rare enough to feel different. Drag the crowd size.
The best evidence about life at 140, and its surprise ending
Lewis Terman followed more than 1,500 California children selected largely for IQs near and above 140, for decades. Click through what happened.
Extra points predict less, but not nothing
Research on creative and professional achievement suggests that above roughly 120–140, more IQ predicts less about who reaches the top; drive, opportunity, practice, openness and conscientiousness take over. But Wai's analyses of US elites and the SMPY data find ability still matters within the top 1%, where higher scores predict more patents and tenure. A 140 buys a ticket to elite arenas; winning there is mostly up to what the test never measured.
Folklore with a kernel of plausibility
Almost no historical figure took a modern test. Famous numbers are retrospective estimates (Catharine Cox's 1926 study of eminent figures is the classic) or press assertions. Chess players, writers, actors and entrepreneurs get placed "near 140" in popular lists with little basis.
Ask which test, which year, how recently normed
Raw performance rose about 3 points a decade through the 20th century, so a 140 on old norms would likely read lower on a current test. Gains have slowed or reversed in some countries recently. A 140 from a current Wechsler or Stanford-Binet is the gold standard; a free online 140 is uncalibrated and usually inflated.
The bottleneck is almost never more intelligence
Percentiles and crowd counts are computed from a normal distribution (mean 100, SD 15). The 1916 labels are Terman's historical wording, shown for context; several are now considered offensive and aren't used clinically. Terman, Cox, Feynman, Wai and SMPY points summarise published accounts, not this site's data.