Money WondersPlay

Saving & Compound InterestCompound Interest

The Rule of 72

Divide 72 by the rate to see how fast money doubles

One number, 72, tells you how fast any money doubles, and an Italian wrote it down in 1494. How does it work?

You'll find out

  • How long 6% takes to double
  • How close the shortcut gets
  • Why it works on prices too

Why it matters

Every rate, on savings, loans or prices, hides a doubling time. The rule of 72 shows it in seconds.

About 3 min6 interactive slides · 5 questionsLesson 40 · Zone 5

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