Hermione Granger IQ

Hermione Granger's IQ is about 147 (range 138 to 156) for her age: she solves logic puzzles, deduces the basilisk and Lupin's secret, but sometimes trusts rules over people.

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Key facts

Estimated IQ
IQ 147
Range
138 to 156
Compare with
Albus Dumbledore, Lisa Simpson, Armin Arlert and Kurisu Makise
Confidence
Medium. A fair amount of evidence, with some gaps.
Franchise
Harry Potter. Harry Potter novels (1997 to 2007) and the film series

Fan analysis by the LifeScore Editorial Team, reviewed September 2026. Contains mild spoilers. How we estimate

What is Hermione Granger's IQ?

Hermione is the best reasoner in the trio, and the books give real cases and not just grades. She works out what is petrifying the school, spots that Lupin is a werewolf, catches a journalist who has been spying on them and impersonates a Death Eater to rob a bank vault. That puts her clearly in the exceptional band for a teenager. She is not higher because her deductions are usually prompted by a book or a clue, and she errs when she has to judge people, not texts.

Age-normed for a child and teenager, from about 11 to 17.

How they score

Six ratings out of ten, each based on what is shown on the page or screen. They show how the estimate is built; they are not averaged into it.

DeductionSolving new problems from thin information
8/10
StrategyMulti-step plans that account for other minds
7/10
KnowledgeDepth and breadth of what they know
9/10
InventionBuilding or devising something genuinely new
6/10
AdaptabilityRecovering when the plan breaks
8/10
Reading peopleUnderstanding what other people want and will do
7/10

Scene-by-scene evidence

  1. The potions riddle

    Strong evidence

    Harry Potter and the Philosopher's Stone

    The last room before the Stone holds a row of seven bottles, with three of poison, two of nettle wine, one that leads forward and one that leads back. The clues are in a riddle. Hermione solves it by pure logic, working out which bottle is which and how much each will allow. It is a genuine deductive puzzle solved by a first-year, and it is one of the first times the books rely on her mind to get the story past an obstacle.

  2. Deducing the basilisk

    Strong evidence

    Harry Potter and the Chamber of Secrets

    Hermione links Harry hearing a voice in the walls with the attacks, and realises the monster is a basilisk moving through the pipes. She confirms it in a library book, then tells Penelope Clearwater to look around corners with a mirror. The girls are found petrified instead of dead, and the torn page in Hermione's hand tells Harry and Ron the answer. Research, deduction and a protective step, all before the adults have worked it out.

  3. Working out Lupin

    Strong evidence

    Harry Potter and the Prisoner of Azkaban

    Hermione notices that Professor Lupin's illness lines up with the phases of the moon, and combines that with a boggart lesson and a werewolf essay set by Snape. She concludes he is a werewolf and says so to Harry and Ron, well before the revelation on the page. The inference needs a calendar, a memory for small details and the willingness to reach an uncomfortable conclusion about a teacher she likes. It is a clean piece of evidence-gathering.

  4. Catching Rita Skeeter

    Strong evidence

    Harry Potter and the Goblet of Fire

    Hermione is the one who works out how the reporter is getting private information. A puzzle about how anyone could overhear them leads her to realise that Skeeter is an unregistered Animagus who turns into a beetle. She catches her on a windowsill and traps her in a jar. Hermione had to notice a beetle in odd places and remember the markings around its antennae. It is a small mystery she solves by spotting a pattern others had dismissed.

  5. Enchanting the coins

    Moderate evidence

    Harry Potter and the Order of the Phoenix

    For Dumbledore's Army, Hermione enchants a set of fake Galleons so that members can be told the time of the next meeting without anyone noticing. It is a Protean Charm applied in a new way, and it works for a whole club of students under the nose of a suspicious High Inquisitor. Adapting a known spell to a new communication problem is her best on-page sign of invention, though she builds on existing magic rather than creating a new branch of it.

  6. Robbing Gringotts as Bellatrix

    Moderate evidence

    Harry Potter and the Deathly Hallows

    Hermione impersonates Bellatrix Lestrange with Polyjuice Potion to reach a vault and take a Horcrux. Earlier in the book she also puts a memory charm on her parents for their safety and packs a beaded bag with the supplies the three of them need to survive on the run. These are sustained plans under uncertainty, carried out with stress and limited resources, and they are what the older-teen part of the estimate rests on.

What holds the number down

  1. The cat hair

    Harry Potter and the Chamber of Secrets

    Hermione takes a hair from Millicent Bulstrode's robes for the Polyjuice Potion, but it turns out to be a cat's, and she becomes part cat. She spends weeks in the hospital wing and misses the investigation of Slytherin. It is a rare practical error, and it comes from not checking a source she assumed was safe.

  2. Panic in the Devil's Snare

    Harry Potter and the Philosopher's Stone

    When the plant grips them, Hermione panics and cannot recall a way out, until Ron reminds her that she is a witch and should use magic. She then remembers the plant dislikes light and heat and conjures flames. The knowledge was there, but under pressure she needed a prompt.

  3. Misreading the house-elves

    Harry Potter and the Goblet of Fire

    Hermione founds S.P.E.W. to campaign for house-elf rights and leaves knitted hats around the school, assuming the elves want to be freed. Most of them do not. She judged from principle without asking, which is a typical blind spot for a student who trusts rules and arguments over how individuals actually behave.

Why 147, and not higher or lower

Age-normed, Hermione reasons like a much older student: multi-step logic, research under time pressure and quick uptake of new material. That fits the 145 to 159 band, which asks for sustained feats in at least two areas, and she has deduction and learning speed, with planning as a third. Invention is only average for the setting, since her best ideas repurpose known spells. Her errors are small and human, and they trim the estimate without capping it. The fan claim of 160-plus on the strength of her marks ignores that she is defined more by diligence than by leaps.

IQ estimates for fictional characters are fan analysis: an argument from what the story shows, not a measurement. Read the full method and the standards we hold every profile to.

Hermione Granger's personality and MBTI type

Fans most often type Hermione Granger as ESTJ. Fans are split on Hermione's type. ESTJ and ISTJ are the most common typings, for her love of rules, structure and duty. Some argue for INTJ based on her strategic side in the later books.

Openness
High
Conscientiousness
Very high
Extraversion
Moderate
Agreeableness
Moderate
Neuroticism
Moderate

Hermione's defining trait is conscientiousness: organised, hardworking and responsible. Her openness is high for ideas but lower for anything she sees as woolly. She is kind but bossy, and she worries, especially about exams.

Personality typing is interpretive. It describes how Hermione Granger behaves in the story and does not affect the IQ estimate.

The debate

Fans argue about whether Hermione is actually the smartest character in Harry Potter, or just the hardest working, and whether she outclasses Dumbledore for pure reasoning. We think she is the smartest of her generation at Hogwarts and clearly a gifted reasoner, but not on Dumbledore's level for strategy. Dumbledore reads people over decades, while Hermione is a fast learner in her teens. Age-normed, her estimate is high, and it is the best in the trio, though not in the setting.

For a real-world parallel, Lovelace was a young woman who out-studied her era and saw further than the men around her, writing the first published algorithm for a machine that did not exist yet. Hermione's mix of study and imagination fits the comparison. See Ada Lovelace's IQ estimate.

Hermione Granger IQ: frequently asked questions

What is Hermione Granger's IQ?

The books give no figure. We estimate about 147, with a range of 138 to 156, age-normed for her years at Hogwarts, based on her puzzle-solving, research and planning across the whole series. Treat it as a fan estimate.

Is Hermione smarter than Harry and Ron?

Yes on reasoning and knowledge. Harry has instinct and courage, and Ron is good at strategy, as in the chess game, but Hermione solves the puzzles and does the research that gets the trio through most of the plot.

Is Hermione smarter than Dumbledore?

No, in our reading. She is a gifted student and Dumbledore is a gifted adult with decades of strategic experience. She is probably the better test-taker and researcher; he is the better planner and judge of people.

Are you smarter than Hermione Granger? Hermione's IQ is about 147. What's yours?

Hermione's number is an argument from the story. Yours can come from a real test: 25 visual reasoning questions.

Take the IQ test

25 questions · about 12 minutes

Hermione Granger and Harry Potter belong to their respective owners. LifeScore is not affiliated with them. This page is independent commentary and analysis, and estimates are our own opinion.