What IQ do you need for Mensa?
Mensa accepts the top 2 percent. On a standard scale that line falls around 132, but the qualifying number differs by test, and nothing you take at home counts.
The requirement is a percentile, not a number
This is where nearly all the confusion starts.
Mensa’s criterion is the 98th percentile: the top 2 percent of the general population. It is not defined as a specific IQ figure at all.
The IQ number matching that percentile depends entirely on the standard deviation the test uses.
| Scale | 98th percentile is about |
|---|---|
| SD 15 (Wechsler-type) | 132 |
| SD 16 (older Stanford-Binet forms) | 148 |
| SD 24 (Cattell III B) | 148 |
All three describe the same rarity. Someone reporting 148 on a Cattell and someone reporting 132 on a Wechsler are in identical positions.
This is why quoted Mensa numbers vary so wildly online. People compare figures from scales that were never comparable, then argue about the difference. The percentile mechanics explain why a single percentile maps to so many different-looking numbers.
Which tests count
Two routes in.
Mensa’s own supervised admission test. Taken under proctored conditions and scored by Mensa. Format varies by national branch.
A prior qualifying score. Mensa maintains a list of accepted standardised tests, which typically includes several Wechsler scales, Stanford-Binet and, in some countries, certain historical university entrance exams. The list differs by nation and changes over time, so check your own branch’s current list rather than a forum post from a decade ago.
The requirement common to both routes is supervision. An unproctored score, however high, proves nothing to an organisation whose entire criterion is a verified percentile.
Why no online test qualifies
Ours included, and we would rather say so plainly than imply otherwise.
A sixteen-item unproctored screener cannot resolve scores at the 98th percentile with any confidence. Our own scale stops at 145 precisely because a short test cannot discriminate reliably beyond about three standard deviations. Nothing prevents a determined person looking at the page source either, which is an unavoidable consequence of running everything client-side.
If you score highly on our free IQ test and want to know whether it means something, the next step is a supervised test, not another online one.
Any site selling a certificate as Mensa-relevant is misleading you, which is one of the patterns worth recognising in IQ test scams.
If you land just below
A score one or two points under the line is not meaningfully different from one just above it.
Measurement error on a good clinical test runs a few points either way, so 130 and 133 describe the same underlying performance. Most branches permit retesting after a defined interval, and some accept a different qualifying instrument. Treating a near miss as a verdict misreads what the number can support, a point we make more generally in what counts as a good IQ score.
Is it worth joining?
Mensa is a social organisation. It runs local groups, publications, special interest sections and events.
Membership is a hobby, not a credential. No employer treats it as a qualification, and the entrance criterion measures one narrow ability. People who enjoy it enjoy the community, which is a perfectly good reason to join. Expecting it to open professional doors is not.
Key takeaways
- Mensa’s requirement is the 98th percentile, not a specific IQ number.
- That percentile is about 132 on an SD 15 scale and about 148 on SD 16 or SD 24 scales.
- Both routes in require supervision: Mensa’s own proctored test, or an approved prior result.
- No unproctored online test qualifies, including ours.
- A score a point or two below the line is not meaningfully different, and retesting is often permitted.
- Mensa is a social organisation, not a professional credential.