Who Is the Smartest Woman in the World? What Is on Record

No one can be named as the smartest woman in the world. The only woman on record in a Guinness World Records "Highest IQ" listing is Marilyn vos Savant, who appeared from 1985 or 1986 to 1989 with two numbers, 228 and 186, taken on different scales. Guinness retired the category in 1990, so there is no current record holder, and a score from decades ago is not a ranking of women today.

Below: what the record shows and where sources disagree, the difference between a ratio IQ and a deviation IQ, why 228 and 186 cannot be compared, and why the question "smartest woman" has no tested answer.

Who is the smartest woman in the world on record?

Marilyn vos Savant is the only woman we found in a Guinness "Highest IQ" listing. Wikipedia says Guinness listed her under that heading from 1985 to 1989, citing Sam Knight in the Financial Times of 10 April 2009. Mental Floss gives 1986 to 1989. The sources agree that the listing ended in 1989 and that Guinness retired the category in 1990.

We found no other woman listed under Guinness's "Highest IQ", and no Guinness page that ranks women by intelligence. That is the whole record. It is also our answer to related searches such as the smartest female in the world, the smartest lady in the world and the woman with the highest IQ. Our companion piece on who the smartest person living is covers why the question cannot be settled for anyone.

What IQ scores are reported for the woman with the highest IQ?

Two scores are reported, 228 and 186, and they come from different tests. We take both from Wikipedia's article on vos Savant; we could not open the underlying Guinness edition or the Omni article.

• 228: the 1937 Stanford-Binet, Second Revision, taken at age 10. She says her first test was in September 1956 and gave a mental age of 22 years 10 months. The score is self-reported
• 186: the Mega Test, taken in the mid-1980s. Wikipedia reports her raw score as 46 out of 48, a z-score of 5.4 and a standard deviation of 16, which gives 186

The arithmetic fits. Her mental age of 22 years 10 months is 274 months. Divided by a chronological age of 120 months and multiplied by 100, that is 228. And 5.4 standard deviations at 16 points each, added to 100, is about 186. So the figures match the method, whatever one thinks of the tests.

What is the difference between ratio IQ and deviation IQ?

A ratio IQ divides mental age by actual age and multiplies by 100, while a deviation IQ compares a person with others of the same age on a scale with a set mean and standard deviation. The first rewards being years ahead of your age and was the original method. The second is the method used today. Our guide to how IQ scores work goes through both.

Wikipedia's Stanford-Binet article describes the history. Terman multiplied the ratio of mental age to age by 100. The 1960 revision introduced a deviation IQ with a mean of 100 and a standard deviation of 16, though ratio IQ was not eliminated at once. The article adds that scores on the older form L-M in the gifted range "were much higher than those yielded by essentially every other major test". Wechsler tests use a standard deviation of 15.

Why can't 228 and 186 be compared?

They cannot be compared because a ratio score and a deviation score measure different things. A child far ahead of their age can reach a ratio IQ above 200 without being as rare as the number implies.

Here is the test. If 228 were a deviation score with a standard deviation of 16, it would be 8 standard deviations above the mean, or about 1 person in 1.5 quadrillion on a normal curve. The world has about 8.2 billion people alive today, so no norm group could support that. The 186 is rarer than it looks too: 5.4 standard deviations is about 1 in 30 million on the same curve, and a test built on a small, self-selected sample cannot stand behind such a figure. On the usual Wechsler scale the same z-score of 5.4 would read 181, still above the roughly 160 top of standard tests. All of this is our arithmetic.

Can anyone be called the smartest woman in the world today?

No one can, because no test ranks all women and standard tests stop near 160. Our article on why scores stop near 160 explains why even a perfect score would not separate the top few hundred thousand people. The same lack of a common scale applies to any country: our average IQ by country page shows how national averages differ by data source, not just by people.

For famous names, our celebrity IQ profiles show which numbers come from tests, which from estimates and which from legend. Our report on the highest IQ ever recorded sets Guinness's old listing next to the other famous claims.

You can place yourself even if the world's top cannot be ranked. Start with the IQ test on our home page, then read your result with the IQ percentile calculator.

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