DEFINITION of 'Rule Of 70'
A way to estimate the number of years it takes for a certain variable to double. The rule of 70 states that in order to estimate the number of years for a variable to double, take the number 70 and divide it by the growth rate of the variable. This rule is commonly used with an annual compound interest rate to quickly determine how long it would take to double your money.
INVESTOPEDIA EXPLAINS 'Rule Of 70'
Another useful application of the rule of 70 is in the area of estimating how long it would take a country's real GDP to double. Similar to compound interest rates, one can use the GDP growth rate in the divisor of the rule. For example, if the growth rate of the China is 10%, the rule of 70 predicts it would take 7 years (70/10) for China's real GDP to double.
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