Mensa International is the world's largest and oldest high-IQ society, founded in Oxford in 1946. Its single membership requirement: score in the top 2% of the general population on an approved standardized intelligence test.
The top 2% threshold corresponds to an IQ of approximately 132 on the Stanford-Binet scale or 130 on the Cattell scale (which uses a different standard deviation). On a standard IQ scale with mean 100 and SD 15, the 98th percentile is IQ 130.
To join Mensa, you can submit prior qualifying test scores (from certain standardized tests including SAT, ACT, or IQ tests taken within the past 2 years from approved providers) or take Mensa's own supervised qualification test. Many national Mensa chapters have their own admission tests.
The Mensa test typically takes about 2 hours and consists of multiple subtests covering pattern recognition, spatial reasoning, verbal reasoning, and numerical ability. No special knowledge is tested — the focus is on reasoning ability.
What does Mensa membership provide? Social events with other high-IQ people, access to special interest groups (SIGs) on hundreds of topics, a monthly magazine, and arguably the networking opportunity. Critically, research on whether high-IQ societies select for career achievement shows mixed results — IQ is only moderately correlated with real-world success, and Mensa's own roster of members has produced few historically transformative figures.
Frequently Asked Questions
What IQ score is needed for Mensa?
Mensa requires a score at or above the 98th percentile. On a standard IQ scale (mean 100, SD 15), this is approximately IQ 130. On the Cattell scale (SD 24), it is IQ 148.
How hard is the Mensa test?
The Mensa qualifying test is challenging for average scorers but not for people with genuinely high fluid intelligence. It tests reasoning and pattern recognition without requiring specialized knowledge. Approximately 1 in 50 people qualify.
