How to Join Mensa: The Requirements, the Test and the Scores That Qualify

The one rule: top 2 percent

Mensa was founded in 1946 at Lincoln College, Oxford, by the barrister Roland Berrill and the barrister and biochemist Lancelot Ware. Its entry rule is a score at or above the 98th percentile on a standardized, supervised intelligence test. Mensa International puts it plainly: the top 2 percent of the population on a professionally supervised IQ test.

The society has about 150,000 members in more than 90 countries, organized in 48 national groups. American Mensa, the largest, has more than 40,000 members and notes that one person in every 50 qualifies, more than six million Americans. On the standard IQ scale the line sits at 130. The exact 98th percentile is 130.8, so an IQ of 131 is the first whole score above the statistical cutoff.

Qualifying scores by test

American Mensa says it accepts scores from about 200 standardized tests. The selection below comes from lists published by American Mensa's local groups. The full, current list is on us.mensa.org, and several college-entrance tests qualify only if taken before a cutoff date.

Later versions of the dated tests do not qualify. Note also that a qualifying 148 on the Cattell scale is not a Wechsler 148: IQ 148 shows how rare that would be on the standard scale, and the IQ classification chart explains the conversions.

Route one: prior evidence

Many members never sit a Mensa test. They qualify with a score they already hold: an educational psychologist's report, a school's CogAT or Stanford-Binet result, or an old SAT. Mensa International asks applicants to send the documentation with details of when and where the test was taken.

Costs and timing vary. A Metropolitan Washington Mensa page lists $60 for verifying prior scores, and the fee is sometimes waived: Mid-America Mensa announced a free prior-evidence review for November 2025. British Mensa accepts a full educational psychologist's report or documentary evidence of a professionally administered IQ test, and quotes four to six weeks for processing.

Route two: the Mensa admission test

In the United States, the Mensa admission test is a supervised session of two timed tests with a short break, about two hours in all. Candidates must be 14 or older on the test date. A result at or above the 98th percentile on either test qualifies. Local chapters list $60 for a group session and $99 for private testing.

Retesting rules have loosened. An older chapter page states the test can be taken only once; current chapter pages say a candidate who does not qualify may test again after at least eight weeks. Some European groups are stricter: Mensa in Germany and Austria limits applicants to one test a year and three attempts in total.

In Britain, the supervised test costs £49 and runs either online under supervision, in about 1½ hours, or in person, in about 2¼ hours. Candidates must be over 10½. British Mensa's £15 home test returns only an indicative score, not an admission result.

If your country has no national Mensa

Applicants in countries without a national Mensa join Mensa International directly as Direct International Members. Mensa International lists four routes: submit prior evidence from a licensed psychologist; sit a supervised test while visiting a country with a national Mensa; attend a session run by visiting testing officers from a neighboring national Mensa; or take an online adaptive test that Mensa International said was expected to go live in 2025. Confirm the status of that last option before planning around it.

What it costs

Mensa charges twice: once to test and every year to belong. Fees are set nationally and change, so treat the figures below as examples, not quotes.

American Mensa publishes its current dues on us.mensa.org. In every country, a practice score costs less than an admission test and qualifies for nothing.

How to prepare for the test

Familiarity helps a little; fatigue hurts a lot. A 2018 meta-analysis in the journal Intelligence, covering 122 studies and more than 153,000 people, found that scores on cognitive ability tests rise by about a third of a standard deviation on a second attempt, roughly 5 IQ points, and stop rising after the third. Part of that gain is simply knowing the format.

Sensible preparation means seeing the item types in advance, sleeping properly and arriving early. Mensa's own unofficial practice test and our free IQ practice test both serve that purpose; neither counts toward admission. The Mensa IQ test guide describes the question types, and are online IQ tests accurate explains why a practice score is only a screener.

Near misses: 128, 129 and the margin of error

Mensa applies its cutoff to the score on the report, not to the ability behind it. Every score carries a margin of roughly five points, so a 128 or a 129 may belong to someone who would test above 130 on another day, but it does not qualify. A 132 clears the Wechsler line with little to spare.

A candidate just short has two options: prior evidence from a different approved test, or a retest once the waiting period has passed. The IQ rarity chart sets out how rare each score is, and what IQ is the top 1 percent covers the next line up.

Editorial standard: IQ figures for historical figures are retrospective estimates and are labeled as such; scores for living people appear only when the person disclosed them or a reputable outlet reported them. Corrections: contact the editors.