A mental shortcut: 72 ÷ annual return ≈ years for money to double.
At 8%, money doubles about every 9 years; at 6%, every 12. It also works for inflation and debt — 24% credit card interest doubles what you owe in ~3 years if unpaid.
Example: 72 ÷ 8 = 9 years to double.
FAQ
What is Rule of 72 in simple terms?
At 8%, money doubles about every 9 years; at 6%, every 12. It also works for inflation and debt — 24% credit card interest doubles what you owe in ~3 years if unpaid.