| 72 | The number 72 is used to approximatley calculate your money's doubling time in years. Ex. You have $10 000 and recieve %6 interest a year, using the rule of 72 it will take roughly twelve years at 6 percent interest for you to accumulate $20 000. All you need to do to calculate the doubling time is divide 72 by the compound interest rate you receive annually. |
