All Fermi answers
Fermi #64 · Question 1

How many times does the name "Harry" appear across all seven Harry Potter books?

Explore the official answer and the simple reasoning behind this Fermi estimate.

1QUESTION 1 OF 3

Answer & explanation

The official answer, with Fermi’s reasoning step by step.

Answer & explanation

Official answer

16,557

times

How to estimate it

Fermi’s official “Napkin math”

Seven books, maybe 500 pages each. How often does Harry's name show up on a page? He's in almost every scene, so maybe 5 times.

Books
7
Pages per book
× 500
Harry per page
× 5
7 × 500 × 5
≈ 17,500

Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.

Source calculation & reference
Word 'harry' across all seven books (tidytext word count)
16,557
Most in Order of the Phoenix
3,730
Least in Philosopher's Stone
1,213
Series total
16,557

Reference cited by Fermi: UC Business Analytics R Programming Guide (University of Cincinnati), word-frequency analysis of the full text of all seven books: 'harry' appears 16,557 times

How close was your guess?

Your comparison will appear here.

Compare by ratio: divide the larger number by the smaller one. The closer to 1×, the better.

Skip to main content