Day 22 Week 4 Day 1: The Simplest Shortcut in Finance Compounding Divide 72 by your interest rate and you get the number of years it takes your money to double. That is the Rule of 72.... Divide 72 by your interest rate and you get the number of years it takes your money to double. That is the Rule of 72. Lesson Locked This Lesson Is For Paid Subscribers Subscribe to access the full lesson, commentary, and your day-by-day course progression. Start Learning - $9.99/month View Full Syllabus ← Previous Lesson Back to Browse Next Lesson →