Compound Interest and the rule of 72

the compound interest and the rule of 72

The rule of 72 says that in order to find the number of years required to double your money at a given interest rate, you can just divide the interest rate into 72.
For example, if you want to know how long it will take to double your money at eight percent interest, divide 8 into 72 and get 9 years.The rule of 72 is remarkably accurate, as long as the interest rate is less than twenty percent.You can also run it backwards. If you want to double your money in six years, just divide 6 into 72 to find that it will require an interest rate of about 12 percent.