A great tool to have in your toolbox when you look at your investments earning compound interest is the “Rule of 72”. The Rule of 72 is a mathematical principle that estimates the time it will take for an investment to double in value and is a basic formula anyone can use.
Simply take the number 72 and divide it by the interest earned on your investments each year to get the number of years it will take for your investments to grow by 100% or double.
