I’ve seen claims online about people having IQs of 200+ or even higher, but I’m skeptical about whether scores that extreme are even measurable. Most tests I’ve looked at seem to cap out around 160, so how do these super high numbers even get calculated?
Is there actually a theoretical maximum IQ, or does it just become statistically meaningless past a certain point because there aren’t enough people to norm against? Also, are those famous historical figures with alleged IQs of 180-200 (like Einstein) actually verified, or are those just estimates people made up?
Most modern tests like the WAIS cap around 160 because scores beyond that become statistically unreliable—there just aren’t enough people in that range to properly norm the test. Those 200+ scores you see online are usually from sketchy internet tests or outdated scoring methods. Past 160, the numbers become pretty meaningless since you’re already in the top 0.003% of the population.
There’s no real “maximum” IQ theoretically, but practically speaking, scores above 160 are basically unverifiable. Einstein’s alleged 160 IQ? Total myth—he never took an IQ test. Those extreme scores are either from poorly designed tests or just made-up estimates. Legitimate tests don’t go that high because the statistical models break down when you’re measuring one-in-a-million rarity.
Under the old quotient IQs (a mathematical formula that has been out of date for decades), it was possible for children to score over 200 on an IQ test – usually the Stanford-Binet. Today, those are rare.
You’re right that most IQ tests have much lower ceilings. It’s HARD to write a test with a super high maximum score. Not only do you have to create questions that accurately measure intelligence at that level, but the test needs a norm sample large enough find people in that range. Here’s why that’s hard:
IQ of 145 –> top 0.135% of the population, or 1 in 740 people. (This is a typical maximum IQ on many tests.)
IQ of 150 –> top 0.043% of the population, or 1 in 2,331 people.
IQ of 160 –> top 0.003% of the population, or 1 in 31,250 people.
In theory, the highest IQ for someone in the US (with a population of over 300 million) is 187. So, you’re right to be skeptical of IQs above 200.
As you can see, the higher the IQ is, the rarer it is. To reliably have a maximum much above 145, the norm samples have to be huge (although there are some statistical properties of IQ scores that mean that the maximum score can be easily extrapolated beyond the size of the norm sample).
Most test creators don’t even try to have IQs higher than 145 on their test because 99.865% of examinees don’t need a score that high. But there are some exceptions. The Stanford-Binet 5 has a maximum score of 160. The Wechsler Intelligence Scale for Children, Fifth Edition has “extended norms” that provide scoring rules that permit a maximum IQ of up to 210. I’m skeptical that values that high are ever needed. But there probably are some psychologists who use those extended norms to estimate scores in the 150s or 160s (perhaps higher).
@CloverL While I agree that scores from standard IQ tests (like the WAIS-IV) stop being reliable around 145-150, it’s not impossible to measure the extremes. There are high-range psychometric tests, often non-timed and using obscure problem sets, specifically designed to bypass the ceiling effect. Groups like the Mega Society use these tests.
@brant-briede606 The biggest problem I see with the “Mega Society” model is the issue of self-selection bias. The only people taking these obscure, often non-timed tests are those who are already highly intelligent, enjoy taking tests, and actively seek out these communities. The resultant scores are only meaningful within that pool of dedicated test-takers and cannot be accurately translated back onto a general population distribution. The scores are, statistically speaking, tautological: they measure the ability to pass the Mega Society test, not a verified position on the global IQ bell curve.
Don’t you thing might be overstated? After all, standardized IQ tests like the WAIS also face self-selection, yet we still consider them valid. The real question isn’t whether self-selection exists, but whether it systematically biases the results enough to invalidate the scores, and whether there are statistical methods to correct for it.
This seems like you’re overthinking something that doesn’t really matter in practice. IQ scores above 160 are basically just statistical noise. The obsession with finding the highest possible IQ feels more like internet bragging rights than genuine curiosity about intelligence measurement.