The largest and oldest high IQ society in the world, founded in 1946 in Oxford, England. Mensa is a non-profit organization, consisting, in the late 2010s, of around 134,000 members in 100 countries and in 54 national groups. The largest national groups are: American Mensa (more than 57,000 members), British Mensa (more than 21,000 members) and Mensa Germany (more than 13,000 members).
Larger national groups are further subdivided into local groups. Members may also form Special Interest Groups (SIGs) at international, national, and local levels; these SIGs represent a wide variety of interests, ranging from motorcycle clubs to entrepreneurial co-operations.
Mensa’s requirement for membership is a score at or above the 98th percentile on certain standardised IQ or other approved intelligence tests, such as the Stanford–Binet Intelligence Scales. Only some national Mensas accept child members; many offer activities, resources, and newsletters specifically geared toward gifted children and their parents. Both American Mensa’s youngest member and British Mensa’s youngest member joined at the age of two.
Notable Mensans include American biological anthropologist Grover Krantz, computer designer and software publisher Adam Osborne, Brazilian racing driver Lucas di Grassi, Markus Persson, Swedish creator and developer of Minecraft and fictional character Lisa Simpson.