Rule of 72 from Gary Jones Insurance Agency in California

Rate of return %	Years	Rate of Return %	Years	To find out how long it will take an amount of money to double, divide 72 by the rate of return. For example, a $10,000 investment earning a fixed 2.5% will take 28.8 years to double to $10,000 (72 divided by 2.5 is 28.8). If $10,000 earns 10% a year, it will take only 7.2 years to double your money (72 divided by 10). You can also determine the rate of return if you divide the number of years it took to double your money into 72. For example, if it took 12 years for you to double your investment, that means you were earning 6%. To determine how long it will take you to double your money or figure out the rate of return you received on your investment,m refer to the chart on the left. The chart assumes that the investment earns a fixed rate of return (and does not take into account the usual 1st year bonus 1% many our annuities have) and is not subject to principal fluctuations. Many investments will fluctuate in value and this chart is for instructional purposes only and does not depict or predict the return on any specific investment.
2.00	36.0	2.50	28.8
3.00	24.0	3.50	20.5
4.00	18.0	4.50	16.0
5.00	14.4	5.50	13.0
6.00	12.0	6.50	11.0
7.00	10.3	7.50	9.6
8.00	9.0	8.50	8.5
9.00	8.0	9.50	7.6
10.00	7.2	10.50	6.9
11.00	6.5	11.50	6.3
12.00	6.0	12.50	5.8
13.00	5.5	13.50	5.3
14.00	5.1	14.50	5.0
15.00	4.8	15.50	4.6
16.00	4.5	16.50	4.4
17.00	4.2	17.50	4.1
18.00	4.0	18.50	3.9
19.00	3.8	19.50	3.7
20.00	3.6	20.50	3.5
21.00	3.4	21.50	3.3
22.00	3.3	22.50	3.2
23.00	3.1	23.50	3.0
24.00	3.0	24.50	2.9
25.00	2.8	25.50	2.8