Rule of 72
Calculate how long to double your investment
9
Years to Double Your Money
72 ÷ 8% = 9 years
$10,000 at 8%
→ $20,000 in 9 years
$10,000 at 8%
→ $40,000 in 18 years
$10,000 at 8%
→ $80,000 in 27 years