IQ 161

161 is 4.07 standard deviations above the mean. On a bell curve that works out to about 1 in 41,900 people, which would mean about 1,600 in the UK and about 190,000 worldwide. The bell curve is a model, though, and at this height it is doing most of the work.

Major individually administered adult tests typically report full-scale scores up to about 160. A reported number above that usually comes from extended norms, a different scale or extrapolation.

No test has enough people in its norm sample to check its accuracy at 161. In a 2,200-person sample the bell curve expects about 0.05 people at 161 or higher.

Most very high numbers you see online come from one of a few sources, and knowing which one produced a 161 tells you how much weight to put on it.

• Different scales. Some tests use a standard deviation of 24, so a 161 there is about 138 on the usual SD 15 scale.
• Historiometric estimates. Researchers such as Catharine Cox (1926) estimated IQs for famous people from biographies. Some of her adjusted estimates went above 200. They are educated guesses, not test results.
• Repetition without a source. Numbers attached to celebrities are often copied from site to site with no test report behind them.

42 of the historical profiles on this site carry an estimate of 160 or more, and 20 reach 161 or higher. Isaac Newton and Leonardo da Vinci are the classic examples. Their numbers are retrospective judgements based on their work, not test scores.

As far as anyone knows, Albert Einstein never took an IQ test. The 160 figure repeated online is an estimate. See the Einstein profile for what it rests on.

On a bell curve with a mean of 100 and a standard deviation of 15, about 0.0024% of people score 161 or higher. Applied to whole populations:

Going from 156 to 161 makes a score 4 times rarer, and going on to 166 multiplies the rarity by another 4.4. Near 161, each single point adds about 33% to the rarity.

What your 161 could really be. If you retook a well-made test, landing at 156 or at 166 would be unremarkable. That is the difference between beating 99.99% and 99.99945% of people, and short online tests are noisier still.

Which scale was it on? A 161 reported on an SD 16 scale converts to about 157 on the usual SD 15 scale, and one from an SD 24 scale (seen in some Cattell-style results) to about 138. Check which scale your score report used.

Estimates this high are reserved for a small group of scientists, artists and thinkers. These sit near 161. Treat these as informed guesses from biographies rather than results. Each profile sets out what its estimate rests on.

The scores one and five points either side of 161, plus the round numbers from 100 to 150, side by side. Tap any score for its full page.