## Rule of 72

The Rule of 72 is a simple formula used to estimate the length of time required to double an investment. The rule of 72 is primarily used in off the cuff situations where an individual needs to make a quick calculation instead of working out the exact time it takes to double an investment. Also, one is more likely to remember the rule of 72 than the exact formula for doubling time or may not have access to a calculator that allows logarithms

## $$\frac{72}{r}$$

Here,r=rate expressed as a whole number

ENTER THE VARIABLES TO BE USED IN THE FORMULA