What Does Ami’s 300 IQ Score Actually Mean?

Ami and her Rumored 300 Point IQ Score

Ami and Her Rumored 300 Point IQ Score

One of the first and most important things to mention when talking about Ami’s enormous IQ is that (in the manga, at least) it’s actually an unsubstantiated rumor that she has a 300 point IQ in the first place,1 spread by her classmates in Juban junior high school.

Ami Mizuno!

She got full marks on all subjects and is ranked number one in Japan.

They say she has an IQ of 300, y’know…

She’s not human!

She also scored first place in a national exam for all core academic subjects with a score of 900/900, which at least does prove that she is incredibly smart and that it isn’t all just schoolyard gossip, as if we needed any further justification. Now, in case you’re curious where this 900 figure comes from, Japanese junior high schools hold mid-term and final exams on the five core subjects (Japanese, Social Studies, Math, Science, English) and four practical skill subjects (Music, Art, Physical Education, Technology and Home Economics).2 Assuming that this was the base which was used for the national exam Ami supposedly took part in, that means she got a full 100 points in each of the nine subjects—including PE! Talk about impressive…

Ami downgraded to a lowly 500 points...

Ami downgraded to a lowly 500 points…

If you look at the re-mastered kanzenban (Complete Edition) manga, you can see that Ms. Takeuchi obviously picked up on this anomaly that Ami is a PE and Home-Ec master and downgraded the test to the five core subjects mentioned above.3 In both cases, however, the person speaking clearly remarks that she’s rumored to have an IQ of 300.

Now that we got that out of the way, what does an IQ score actually mean? We hear about it all the time, and it’s commonly used in television, movies, and other media to impress the audience with the intelligence of a character,4 but we rarely think about what this actually means and, sadly, how mundane the number actually can be. So, how do we calculate your IQ? Simple, really!5

IQ = (Mental Age ÷ Chronological Age) × 100

So in order to get your IQ, we need to know your Chronological Age (i.e., how long you’ve been alive) and your Mental Age (i.e., the age determined through taking a skill-based IQ test).6 For example, if an 8 year old child was capable of solving problems exactly like any other 8 year old, he or she would have an IQ of 100.7 If that same child was not so good at solving brain teasers and was able to solve them at the level of a 5 year old, he or she would have an IQ of  62.5.8

Studying hard to keep those grades up

Studying hard to keep those grades up

Since we know Ami’s age (14) and her IQ is supposedly around 300, it’s relatively simple to do the math and see that a 300 IQ means simply that she has the problem-solving ability of an average 42 year old.9 Now don’t get me wrong, that’s pretty impressive in its own right, especially for a 14 year old. But on the other side of the coin, this should help at least ground things a little closer into reality and explain why, even if her 300 IQ were more than a rumor, she isn’t quite the phenomenon that the huge number implies.

However, in this old-fashioned and simplistic test (which, I should mention, has not been used for years but is generally the one referred to in pop culture) it’s not possible to obtain a score over 170, which takes us back to square one. Or does it? A similarly unrealistically high number has come up in the past, from none other than famed science fiction author and ex-Mensa member, Isaac Asimov. As the (unsubstantiated) story goes, he took an IQ test in the back of a book and got an IQ score of 135,10 but was dissatisfied with the fact that though the test penalized for being slow (less questions answered = a lower score), it didn’t reward you for being fast. Since he finished the test in half the time, he doubled his score to 270.

All work and no play...

All work and no play…

Assuming the possibility that the people giving Ami the test were also using dubious means (which isn’t all that uncommon, as was the case with Marilyn vos Savant,11 whose own IQ score of 228 is highly disputed due to shaky math by the test-givers), and her score comes from having rushed through the test in record time and obtained an actual base score of 150, this would put Ami at a much more reasonable level of having the problem-solving capacity of a 21 year old, and also in line with scores seen among normal Mensa members.

So what does this all mean, in the end? Basically, the take home lesson is that Ami is absolutely a brilliant character (as she proves both scholastically and in helping her friends out of an untold number of dangers), but for all the talk it gets, her IQ should probably not be considered nearly as much as it is. More than likely, it’s purely a rumor, and even if it weren’t, Ami should be seen more as a role model for what you can do with study and hard work, and not just a number. Sailor Moon Says!12

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  1. p. 49 of vol. 1, original Kodansha release of the manga
  2. See Regular Examinations (Wikipedia) (Japanese)
  3. p. 55 of vol. 1 of the Complete Edition re-release in 2013
  4. For more examples of fictional characters with incredibly high IQs, see Improbably High I.Q. (TVTropes)
  5. Only ‘simple’ if we’re using the common-day, highly inaccurate, and established in the 1930’s Stanford-Binet system. The field of IQ analysis is huge and far beyond the scope of this, so forgive me for sticking only to the pop-culture analysis
  6.  See Intelligence Quotient (Wikipedia)
  7. (Mental Age (8) ÷ Chronological Age (8) × 100)
  8. (Mental Age (5) ÷ Chronological Age (8) × 100)
  9. 300 ÷ 100 × Chronological Age (14) = Mental Age (42)
  10. Or 150, depending on the source of the story
  11. The 1986-1989 holder of the “Highest IQ” listing in the Guinness Book of World Records before the category was retired in 1990. See Marilyn vos Savant (Wikipedia)
  12. Sorry, I had to do it… see Sailor Moon Says (YouTube)

5 thoughts on “What Does Ami’s 300 IQ Score Actually Mean?

  1. Great analysis, as always! IQ is a really misunderstood concept so it’s nice to have its shortcomings explained like this, and that it’s not just “really really smart = biggest number!!!” I really liked the insight into the Japanese grading system.

    In the interest of pedantry, Ami does confirm her IQ is 300 in the first musical (“Dark Kingdom Fukkatsu Hen”). Zoisite (in disguise as “Student B”) asks her flat-out what her IQ is, and she replies with an enthusiastic “300!”
    Of course, the musicals are their own special kind of canon, and I think it makes more sense as a schoolyard rumour. I can imagine that even if Ami were told she had an IQ of 150/a rounded-up 300, she wouldn’t put much stock in it, and only bring it up when asked. She’d probably think it was funny!

  2. Of course, anyone with parents knows that once you leave school, your ability to solve problems goes DOWN, so being as good as a 42-year-old isn’t much.
    If I went to school with Ami, my only numerical concern would be getting her phone number ;3

  3. This article is based on true foundations but is wrong in many ways. First off, it is true that the IQ tests were originally designed and are also still used to track the development of a child compared to other children, and based on the score the child of for example 6 years of age could be said to have the abilities of a 12 year old kid or a 4 year old.

    The fact is that it is no more the sole objective of the tests, for example, IQ tests for adults serve to evaluate the abilities of the individual without the comparison for other ages, it would not make to do so since at a certain point of your life your development is concluded and cognitive abilities star to deteriorate at a certain age, a 24 years old with an high score would not be said to have the cognitive abilities of a 94 years old, for that would be grotesque, it would mean a lower development that what this individual should have, but not even of a 42 years old, for between a 24 years old and a 42 years old there is not appreciable difference in cognitive development and skills, it would be as though the 24 years old was as an average individual of his age, this is why this article is wrong when it says that Mercury’s 300 IQ equate to the cognitive abilities of a 42 years old, because it may very well equate to a 16 years old abilities if that was the case, since even though the brain is not fully developed yet, individuals of 16 years of age score already on average the same in adult IQ tests as fully mature adults.

    You would probably say as a rebuttal that Mercury is 14, so the scoring system for the tests she must have taken must have been adjusted to take her age into account, while this is probably the case the cognitive abilities of a 14 years old are not much lower than adult ones, a score pf 100 for a test for 14 years old individuals equate to a score of 90 in an adult test, by this we can calculate that Mercury has still a score of well over 250 for adults scores, well over the IQ measured or estimated for every great mind of Mankind that ever lived, so she possesses abilities far superior to any other.

    • While I agree that there have been many advancements in how IQ tests are conducted and interpreted in recent years, we do need to also take into account that Sailor Moon is a manga from 1992 and the statement of her having an “IQ of 300” would have only been based on IQ tests conducted 1) in Japan; and 2) prior to 1992.

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