Membership Reference

The recognized full-membership list by the USIA is from 2 sigma to 5 sigma, in which “sigma” applies to “S.D.” or standard deviation. For example, Mensa = 2 sigma (1:50 or 1-out-of-50 in the general population), when S.D. equals 15, 16, or 24 , means 3 times 15, 16, or 24, plus 100, or 130, 132, and 148, respectively. Please make sure the list is for the reference of the official USIA Qualifications.


2 Sigma (1-out-of-50), top 2%
IQ 132, SD16 Mensa
IQ 137, SD16 Intertel
IQ 137, SD16 Top One Percent Society
3 Sigma (1-out-of-1000), top 0.1%
IQ 148, SD16 Three Sigma Intelligence Society
IQ 149, SD16 Triple Nine Society
IQ 150, SD16 One in a Thousand Society
4 Sigma (1-out-of-30,000), top 0.003%
IQ 164, SD16 Four Sigma Intelligence Society
IQ 164, SD16 Prometheus Society
IQ 164, SD16 Epimetheus Society
IQ 176, SD16 Mega Society
IQ 176, SD16 Omega Society
5 Sigma (1-out-of-3,500,000), top 0.00003%
IQ 180, SD16 OLYMPIQ Society
IQ 180, SD16 Esoteric Sigma Intelligence Society