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Fictional Characters

What is Light Yagami’s IQ?
Top of the national rankings, in a story that never gives a score.

A cosplayer in costume as Light Yagami, photographed at Kuantan CosWalk in 2017
Light YagamiFictional · 2003 onward

Death Note never assigns Light Yagami an IQ, and the figures circulating online are fan estimates. What the story does give is unusually concrete for fiction: a national examination ranking, and a two-year deduction contest with an opponent of stated equal standing.

Our estimate170–190
MethodCharacter analysis
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Last reviewed August 2026
Our estimate

Light Yagami’s estimated IQ

IQ Metrics estimate170–190Character analysis (fiction)
What the estimate rests on
  • Introduced as the top-scoring student in Japan on the national mock examinations — the story’s own measurement, and the only quantified statement it makes about him.
  • Enters To-Oh University joint-first with L, the two of them delivering the freshman address together. The tie is written deliberately: it establishes the antagonists as matched.
  • Sustains a two-year deception against a task force with his own father on it, while under direct surveillance for part of that period.
  • The central contest with L is conducted almost entirely by inference from constrained information — deducing rules, testing them at low cost, and reasoning about what the opponent can and cannot know.

Every fictional estimate has the same defect: the character is only as clever as the plot lets him be, and his opponents only as slow. Light wins his early rounds partly because the narrative grants him a supernatural instrument with rules that happen to reward exactly his strengths. Read this range as a rating of the portrayal, not of a person.

At a glance
First appearance
Death Note chapter 1, December 2003
Created by
Tsugumi Ohba (writer), Takeshi Obata (artist)
In-story rank
First nationally on the mock examinations
University
To-Oh, entering joint-first with L
Canonical IQ
None given anywhere in the source material
Context

What an IQ of 170–190 actually means

Set the claim aside for a moment. If someone genuinely scored in this range, here is what that would represent.

Where a figure of 165–230 would sitOn the standard scale (mean 100, SD 15). This marks the claimed figure — it is not a measured result.
165–230
Below averageLow averageAverageAbove averageGiftedHighly gifted

Average is 100 by construction, and about two-thirds of people fall between 85 and 115. Take the test to place your own score on this scale.

Standard scale, mean 100, standard deviation 15
Score rangeClassificationShare of peopleWhat it indicates
85 – 114Average~68%The range most people fall into.
115 – 129Above average~13.6%Roughly one person in seven.
130 – 144Gifted~2%The threshold most high-IQ societies use.
Above 144Highly gifted~0.1%Figures above this range are extrapolated from the curve rather than measured.

Percentages are approximate and describe a normal distribution. The same number means different things on tests with different standard deviations.

Where would your score sit on that table?

Thirty questions gives you a measured position on this exact scale — your score, your percentile and the ability breakdown behind it.

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Background

Who Light Yagami is

Death Note was written by Tsugumi Ohba and illustrated by Takeshi Obata, and serialised in Weekly Shōnen Jump from December 2003 to May 2006, running to twelve collected volumes.

Light Yagami is a Japanese high-school student, top of the national rankings and the son of a police superintendent, who finds a notebook that kills anyone whose name is written in it. He begins executing criminals, is designated “Kira” by the public, and is pursued by a detective known only as L. The two are established early as intellectual equals, and the story is the contest between them.

The series is unusual among manga of its period for being driven almost entirely by reasoning rather than physical conflict — long sequences of rule-deduction, misdirection and inference about what the opponent knows. That structure is why the character turns up in intelligence discussions at all.

Record

Light Yagami: the documented record

The estimate above rests on this record. Every entry here is a matter of public fact, which is more than can be said for the number itself.

  1. 2003Death Note begins serialisation in Weekly Shōnen Jump.
  2. 2004The task force investigation and the direct contest with L develop.
  3. 2006Serialisation ends after twelve volumes; the anime adaptation begins.
  4. 2007The anime adaptation concludes after 37 episodes.
Where it came from

Where the 165–230 figure came from

Following a claim back to its first appearance is the part almost nobody does — and it is what most people are actually asking.

A cosplayer in costume as Light Yagami, photographed at Kuantan CosWalk in 2017
#1National mock examination rank

Fictional profiles on this site are ratings of a portrayal, and the portrayal here is unusually specific. Most fictional geniuses are asserted to be brilliant; Light is given a measurement the story then uses. He is the top-ranked student nationally, he ties L at the university entrance, and the plot is built out of what those rankings imply.

The placement below the Holmes brothers is deliberate. Sherlock and Mycroft are written as performing feats of observation and inference that have no examination equivalent — reconstructing a stranger’s history from a hat, holding the entire machinery of a government in one head. Light’s demonstrated excellence is academic and strategic rather than perceptual, and academic excellence, even at national rank, describes a narrower thing.

He also sits below Moriarty, and for a reason that is arguable rather than obvious. Moriarty is credited in the stories with a treatise on the binomial theorem written at twenty-one and a European chair — original mathematics, in other words. Light’s record is dominance at examinations, which tests the retrieval and application of known material. Producing new mathematics and topping a national examination are not the same achievement, and the ranking here reflects that distinction rather than any judgement about who would win a confrontation.

How we read a number
PrimaryOhba, T. and Obata, T. (2003–2006). Death Note. Shueisha, Weekly Shōnen Jump; 12 collected volumes.

The source text. Establishes the national examination ranking and the To-Oh tie with L. Contains no IQ figure for any character.

PrimaryDeath Note anime adaptation (Madhouse, 2006–2007), 37 episodes

Follows the manga closely on the points relevant here. Also assigns no numerical intelligence score.

AbsenceNo canonical IQ figure

Neither the manga, the anime, nor the official supplementary material assigns Light Yagami an IQ score. The absence is the finding.

AggregatorFan-wiki and celebrity-IQ republications of “230” and similar

Source URLs and first-appearance date pending audit.

No canonical origin exists. Several pages present these as official; none cites a volume, chapter or interview.

InternalComparison with the Holmes profiles

Placed below Sherlock, Mycroft and Moriarty on the reasoning set out above. Fictional rankings on this site compare portrayals, not characters in a hypothetical contest.

The evidence

The sources behind our estimate

The figures that circulate for Light Yagami, what we were able to confirm, and where the two diverge.

Most widely cited165–230

Figures between 165 and 230 circulate on fan wikis and IQ aggregator pages, usually stated flatly and sometimes attributed to the author. Some pages assert a specific canonical number.

What we foundNo figure appears anywhere in the source material

No IQ score for Light Yagami appears in the manga, the anime, or the official supplementary material. The oft-cited numbers are fan estimates that acquired authority by repetition. The character’s only quantified attribute in canon is his examination ranking, which is a measure of tested academic performance within the story — not an intelligence quotient.

Also published elsewhere
165190230

A sixty-five point spread on a character whose source text gives no number at all. This is the same failure documented across the real people on this site, reproduced for someone who does not exist.

Want a number that does hold up? Every figure on this page is somebody’s claim. Take the 30-question test and get a percentile you can check rather than a figure you have to trust.

Questions

Light Yagami — frequently asked

What is Light Yagami’s IQ?

No figure is given anywhere in Death Note — not in the manga, the anime, or the official supplementary material. The numbers online are fan estimates. Our 170–190 range is a rating of the portrayal.

Is Light Yagami’s IQ 230?

No. That figure has no canonical source. It appears on fan wikis and aggregator pages, sometimes presented as official, but no volume, chapter or interview is ever cited.

Is Light Yagami smarter than L?

The story deliberately ties them — they enter To-Oh University joint-first and share the freshman address. The tie is a writing decision establishing them as matched, so the source text declines to separate them.

How smart is Light Yagami compared to Sherlock Holmes?

We place him below both Holmes brothers and below Moriarty. Light’s demonstrated excellence is academic and strategic; the Holmes characters are written performing perceptual and inferential feats with no examination equivalent.

What was Light Yagami’s exam score?

The story states he ranked first nationally on the mock examinations and entered To-Oh University joint-top with L. It gives rankings rather than raw scores.

Why does a fictional character have an IQ estimate at all?

Because the question is heavily searched and the answers online are invented. This page rates the portrayal against the other fictional profiles here, and says plainly that the source material assigns no number.

How does my IQ compare with Light Yagami?

You can find out in about fifteen minutes. The IQ Metrics assessment is 30 questions, scored on the same 100-mean scale used throughout this page, so your result and the estimate above are at least expressed in the same units — one measured, one inferred. Once you have a number, the leaderboard shows where it would sit, and how we score and norm it explains the benchmarking.

Where does this estimate come from?

From the documented record rather than a test — the method is named above and set out in full under how we read a number. Compare it against the other fictional profiles, starting with Sherlock Holmes.

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Portrait © Matthew Yohe, CC BY-SA 3.0. The background-removed portrait above is a derivative work and is likewise offered under the same licence. · Portrait © Debbie Rowe / The Royal Society, CC BY-SA 3.0. The background-removed portrait above is a derivative work and is likewise offered under the same licence. · Portrait by Christopher Smith, U.S. Department of Health and Human Services — a work of the U.S. federal government, public domain. Background removed for the portrait above.

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