Rule of 72,
Definition of Rule of 72:
Method of computing the time in which an invested sum will double at a specific rate of interest; or for computing the interest rate that will double a principal in a specific period. Formula for time (years): 72 ÷ Annual rate of interest. Formula for interest rate (annual percent): 72 ÷ Number of years.
Meaning of Rule of 72 & Rule of 72 Definition