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Every Harry Potter book ever sold is stacked into one pile. How many kilometres high is the tower?

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The answer

18,000 kilometres

About 18,000 kilometres, a tower of books reaching far out into space.

How to get there

  1. More than 600 million books sold
  2. An average book is about 3 cm thick (assumption)
  3. 600 million × 3 cm = 1.8 billion cm = about 18,000 km

Source: Scholastic: Highlights and Milestones About the Harry Potter Series (accessed October 2026), more than 600 million copies sold worldwide

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