The Rule of 72 and the Rule of 115
How Long Will It Take to Double or Triple Your Investment?

The rule of 72 is a handy mathematical rule which helps in estimating approximately how many years it will take for an investment to double in value at a specified rate of return.

For example, at a 1 % rate of return, an investment will double in approximately 72 years; at a 10% rate of return it will take only 7.2 years, etc.

The rule of 115 is a similar rule that allows one to estimate how long it will take an investment to triple in value.

For example, at a 1 % rate of return, an investment will triple in approximately 115 years; at a 10% rate of return it will take only 11.5 years, etc.

Rate of Return 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 12% Years to double 72 36 24 18 14.4 12 10.3 9 8 7.2 6.5 Years to triple 115 57.5 38.3 28.8 23 19.2 16.4 14.4 12.8 11.5 10.5

Rate of Return 12% 13% 14% 15% 16% 17% 18% 19% 20% 21% 22% Years to double 6 5.5 5.1 4.8 4.5 4.2 4 3.8 3.6 3.4 3.3 Years to triple 9.6 8.8 8.2 7.7 7.2 6.8 6.4 6.1 5.8 5.5 5.2

These rules can also teli you how long before a given item will double or triple in price at an estimated average rate of inflation.

For example, at an estimated average inflation rate of 8%, a loaf of bread will double in price every nine years.