Rule of 72 Calculator is an online personal finance assessment tool in the investment category to measure the time period at which an investment gets doubled based on the Rule 72 method. Rule 72 investment doubling time can be calculated by dividing the title 72 by the given interest rate. For example, if you have invested 1000 USD at 10% compound interest rate per annum, the rule of 72 perform the division 72/10 = 7.2 years required to double the money value based on the rule; an exact calculation gives 7.27 years required to double the money. When it comes to online calculation, this Rule of 72 Calculator can assist you to estimate the required time period.