What is the purpose of Rule of 72?
Do you know the Rule of 72? It's an easy way to calculate just how long it's going to take for your money to double. Just take the number 72 and divide it by the interest rate you hope to earn. That number gives you the approximate number of years it will take for your investment to double.
Rule of 72. The number of years it takes for a certain amount to double in value is equal to 72 divided by its annual rate of interest. Things to know about the Rule of 72. It is only an approximation. Interest rate must remain constant.
For example, the Rule of 72 states that $1 invested at an annual fixed interest rate of 10% would take 7.2 years ((72/10) = 7.2) to grow to $2. In reality, a 10% investment will take 7.3 years to double ((1.107.3 = 2).
The rule of 72 can be used to estimate the following: Given a fixed annual rate of return, how long will it take for an investment to double. The approximate number of years it will take for an investment to double. That compounding can significantly impact the length of time it takes for an investment to double.
Choice of rule
The value 72 is a convenient choice of numerator, since it has many small divisors: 1, 2, 3, 4, 6, 8, 9, and 12. It provides a good approximation for annual compounding, and for compounding at typical rates (from 6% to 10%); the approximations are less accurate at higher interest rates.
The first reference we have of the Rule of 72 comes from Luca Pacioli, a renowned Italian mathematician. He mentions the rule in his 1494 book Summa de arithmetica, geometria, proportioni et proportionalita (“Summary of Arithmetic, Geometry, Proportions, and Proportionality”).
The Rule of 72 is a mathematical formula that estimates how long it'll take an investment to double in value or to lose half its value. To calculate the Rule of 72, you divide the number 72 by the rate of return of an investment or account.
What is the Rule of 72? How is it calculated? The Rule if 72 is a quick way to calculate the length of time it will take to double a sum of money. Divide 72 by the expected interest rate to determine the number of years.
The Rule of 72 applies to compounded interest rates and is reasonably accurate for interest rates that fall in the range of 6% and 10%. The Rule of 72 can be applied to anything that increases exponentially, such as GDP or inflation; it can also indicate the long-term effect of annual fees on an investment's growth.
Variations on the rule also tend to get used because the rule of 72's accuracy is best limited to a small number of low rates of return. It's most accurate at an 8% interest rate, with 6-10% being its most accurate window.
What are some facts about the number 72?
Seventy-two is a pronic number, as it is the product of 8 and 9. 72 is an abundant number, with a total of 12 factors, and a Euler totient of 24. 72 is also a highly totient number, as there are 17 solutions to the equation φ(x) = 72, more than any integer below 72.
Tom Jacobs and John Del Vecchio, authors of the best-selling book What's Behind the Numbers?, have now come out with their next best-seller, The Rule of 72.
In finance, the Rule Of 72 is probably used in preference to the Rule Of 70 as 72 has more whole number divisors (72, 36, 24, 18, 12, 9, 8 and 1) than 70 (70, 35, 14, 10, 7 and 1).
According to the rule of 72, you'll get 72 / 4 = 18 years. If you use the rule of 70, you'll get 70 / 4 = 17.5 years. Finally, if you do the original logarithm calculation, it'll actually take you about 17.501 years to double your money. So, the rule of 70 is a better estimate.
When does money double every seven years? To use the Rule of 72 to figure out when your money will double itself, all you need to know is the annual rate of expected return. If this is 10%, then you'll divide 72 by 10 (the expected rate of return) to get 7.2 years.
The rule of 70 is used to determine the number of years it takes for a variable to double by dividing the number 70 by the variable's growth rate. The rule of 70 is generally used to determine how long it would take for an investment to double given the annual rate of return.
The rule of 70 is a calculation to determine how many years it'll take for your money to double given a specified rate of return. The rule is commonly used to compare investments with different annual compound interest rates to quickly determine how long it would take for an investment to grow.
What is the rule of 70? is a mathematical formula that is used to calculate the number of years it takes real GDP per capita or any other variable to double. the quantity of capital per hour worked and the level of technology.
