“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. The minimum accepted score on the Stanford–Binet is 132, while for the Cattell it is 148.[14] Most IQ tests are designed to yield a mean score of 100 with a standard deviation of 15; the 98th-percentile score under these conditions is 131, assuming a normal distribution.[15]
Most national groups test using well-established IQ test batteries, but American Mensa has developed its own application exam. This exam is proctored[clarification needed] by American Mensa and does not provide a score comparable to scores on other tests; it serves only to qualify a person for membership.”
https://en.wikipedia.org/wiki/Mensa_International
Well I’m definitely not in the top 2% then! My high score at 18 came in at 138.