At 6.5 percent interest how long does it take to double your money to quadruple it

Your money will double in approximately 11 years and quadruple in approximately 22.

Use the Rule of 72 for doubling (72/interest rate = number of years to double) and the Rule of 144 to quadruple (144/interest rate = number of years to quadruple).

The rule of 72 is a simple way to determine approximately when will someone's investment double.

The formula for applying the rule of 72:

number of years = 72 / interest rate = 72 / 6.5 = 11.08 ≈ 11 years

if we want to know approximately when our investment will quadruple, we just multiply 11.08 x 2 = 22.16 ≈ 22 years