Founded in the United Kingdom in 1946, Mensa International is open to anyone with an IQ in the top 2 percent of the populace, meaning the IQ required for acceptance is a moving target. The type of test you take also influences what the organization considers a qualifying score. As the Mensa website notes, a score of 132 on one test may equal a 148 on another. Just two options exist for joining Mensa, which claims 120,000 members in 100 nations: You can take the Mensa Admission Test or submit certified copies of an intelligence test that the organization accepts. Don't expect an easy ride, though. Only one in 50 applicants qualifies for admission.

Taking the Test

Allow two hours for Mensa's primary admission test of two examinations that focus on logic and deductive reasoning. U.S. applicants must pay a $40 nonrefundable fee. If English isn't your primary language, American Mensa offers the cultural fair battery test, which requires you to distinguish relationships in figures and shapes. Scores of at or above the 98th percentile on either test qualify you to join Mensa.

Submitting Your Score

When submitting an intelligence test you've already taken, Mensa International requires a certified copy of your score with the institution's seal, plus your birth date and score indicating how you ranked nationally. Include as much information as possible about the test itself. Mensa also accepts agency or psychology tests sent on professional letterheads. Contact your local Mensa office to see if it accepts your particular test.

Other Considerations

Whether you submit a score or join in Mensa's Oct. 19 national test day, read all instructions carefully. For example, you must request the cultural fair battery test, which is offered only on an as-needed basis. Similarly, if you expect to qualify on a previous score, remember that Mensa does not accept achievement or online tests.