The Rule of 72 Explained In-Depth

What if you could instantly know exactly how many years it will take for an investment to double in value, without needing a complex spreadsheet?

That's exactly what the Rule of 72 achieves. It is a mathematical shortcut used by investors for centuries.

The Formula

For example, if the S&P 500 averages roughly an 8% return per year, you simply divide 72 by 8. The answer is 9. Therefore, any money put into the S&P 500 should roughly double every 9 years.

Visualizing the Rule

• Explore the math with visual examples
• Try our interactive Rule of 72 Calculator