The Rule of 72

The power of compounding can be truly amazing. An investment of only $1000 earning 12% will grow to $30,000 in 30 years, compounded annually. If the investment was only earning 6%, it would be worth less than $6,000 over the same time period.

In order to determine quickly how long it takes to double your investments at different rates, I usually use the rule of 72.