How to Join Mensa: Requirements, History and What the 98th Percentile Means

Mensa is Latin for "table," and the name is deliberate. In 1946, in Oxford, barrister Roland Berrill and scientist Lancelot Ware founded the society to bring together people of high intelligence regardless of politics, religion or social class: a round table where no one sits at the head. The original idea was nearly the opposite of elitism. Today it has more than a hundred thousand members in many countries, the United States among the largest chapters, and the question it hears most is how to get in.

The requirement: 98th percentile, not a fixed IQ

To become a member you must score at or above the 98th percentile on an approved intelligence test. Put differently, your result has to fall in the top 2% of the population, meaning you outperform 98% of the people assessed with that test.

Here is a point that trips up many people: Mensa does not require a fixed IQ number. It requires a percentile, and the same percentile translates into different numbers depending on the test's scale. On scales with a standard deviation of 15, like the Wechsler tests, the 98th percentile sits at an IQ of about 130. On other scales, with a different standard deviation, the equivalent number changes. Saying "you need 130" is a handy simplification, but an imprecise one.

A practical note: if you already took a supervised, approved test in the past, that report may be accepted. Before paying for a new session, it is worth digging up your school or clinical records.

How the qualifying test works

There are two usual routes. The first is to sit the organization's own admission exam, given in supervised sessions by an authorized examiner. The second is to submit earlier results from certain approved tests taken under professional supervision, for example with a psychologist or in a school setting. Each country has a national branch with its own rules and fees, so the sensible move is to check your local chapter's website.

Does an online test count?

No. Online tests, ours included, do not count as proof for admission. Mensa accepts only supervised tests, because without an examiner there is no way to verify who answered, whether someone helped, whether the attempt was repeated or whether anyone looked up the answers. Our test is an entertaining way to explore how you reason, not an official document, and it neither brings you closer to membership nor takes you further from it. If a website offers you a Mensa certificate, be wary.

What it offers and what it does not

Members commonly mention social gatherings, special-interest groups, conferences and the chance to meet curious people. It is a community, not a professional credential: belonging will not make you better at your job or guarantee success. Some people love the experience, and others find it beside the point.

It is also worth keeping membership in perspective. Being a member shows that someone cleared a statistical threshold on a test, not that they are wiser, kinder or better at making decisions. Biases and reasoning errors affect everyone, including people with high scores.

In most countries both the test session and the annual dues cost money, sometimes a meaningful amount, and conditions vary from one national branch to another. Before booking an exam slot, check prices, available dates and whether there are discounts for students or people with fewer resources.

Other high-IQ societies

They exist, with stricter thresholds: Intertel asks for the 99th percentile and the Triple Nine Society for the 99.9th. Each has its own rules about which tests it accepts and how scores are verified. In practice, these societies set themselves apart more by their community and activities than by the title of belonging.

If one interests you, compare what its members actually do: magazines, meetups, forums, local groups. And if none appeals, that is fine. There are plenty of ways to feed your curiosity without paying dues.

If all you want is to see how you reason and compare yourself for fun, our test is one click away and asks nothing in return. If Mensa is a serious goal, the next step is to write to your country's chapter and book a supervised session.