Character · Death Note
Light Yagami's IQ, and what Death Note's IQ Score actually reveals.
How smart is Light Yagami? Smart enough that "Light Yagami's IQ" is one of the most searched questions about Death Note. Here is the defensible read of the mind the show actually builds, the 147/200 IQ Score behind it, and why no invented number does it justice.
The answer
Light Yagami anchors Death Note as one of its central intelligences, and the show earns a 147/200 IQ Score (Stimulating tier) for how seriously it builds that mind. That score is the real, measurable answer the search is circling. The specific IQ figures floating around online are invented; no clinical IQ test applies to a fictional character, and TVI does not fabricate one. We rate the work, not the character, on a published 0 to 200 rubric.
Who Light Yagami is, and what kind of intelligence the show actually depicts
Light Yagami (Mamoru Miyano (Japanese), Brad Swaile (English)) is high-school prodigy who finds a notebook that kills anyone whose name is written in it, the anime's central thought experiment about whether superintelligence applied to moral reform produces utopia or genocide. The character's intellectual signature in the show is tactical-deductive intelligence operating against an equally-matched detective opponent, intelligence-as-moral-corruption, the rare anime protagonist whose cognition is the actual structural antagonist of the story.
This is the part of the question "what is Light Yagami's IQ" that the search engine flattens. The real question, the one viewers are circling, is whether the show treats Light Yagami's mind seriously. That's the question TVI can actually answer.
What the IQ Score reveals about the portrayal
Death Note scores 147/200 (Stimulating tier) and Light Yagami is the rubric's strongest reading of the show's cognitive demand. The Light-vs-L chess match is sustained inquiry into what happens when superintelligence is applied without moral correction, the anime takes its own thought experiment seriously enough to render the protagonist's transformation into a villain without flattening either pole. The IQ Score reflects the structural commitment to actual deductive sequences (not just genre flourish).
For the full score breakdown, Cognitive Stimulation, Educational Value, Craft & Quality, and the rationale, see Death Note on TV Intelligentsia. Or read what an IQ Score is and how it's calculated.
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