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 reason why the rule of 70 is popular in finance is because it offers a simple way to manage complicated exponential growth. It breaks down growth formulas into a simple equation using the number 70 alongside the rate of return.
When buying a home to flip, investors need to estimate how much they believe the property could sell for after it's been renovated. They can then multiply that amount by 70% and subtract it from the estimated cost of renovating the property.
The number of years needed to double a population, assuming a constant rate of natural increase. Doubling time equals 70 divided by the percent growth rate. For example, if a population is growing at 5% annually, it doubles in 14 years; 70/5 =14 years.
How the Rule of 72 Works. 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).
So, if the interest rate is 6%, you would divide 72 by 6 to get 12. This means that the investment will take about 12 years to double with a 6% fixed annual interest rate.
Key Takeaways. The Rule of 72 is a simplified formula that calculates how long it'll take for an investment to double in value, based on its rate of return. 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 70
Imagine that we have a population growing at a rate of 4% per year, which is a pretty high rate of growth. By the Rule of 70, we know that the doubling time (dt) is equal to 70 divided by the growth rate (r). That means our formula would look like this: dt = 70 / r.
The Rule of 72 is a calculation that estimates the number of years it takes to double your money at a specified rate of return. If, for example, your account earns 4 percent, divide 72 by 4 to get the number of years it will take for your money to double.
The Rule of 70 assumes a constant rate of growth or return. As a result, the rule can generate inaccurate results since it does not consider changes in future growth rates.
The doubling time is a characteristic unit (a natural unit of scale) for the exponential growth equation, and its converse for exponential decay is the half-life. For example, given Canada's net population growth of 9 percent in the year 2006, dividing 70 by 9 gives an approximate doubling time of 7.8 years.
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.
Doubling time is the amount of time it takes for a given quantity to double in size or value at a constant growth rate. We can find the doubling time for a population undergoing exponential growth by using the Rule of 70. To do this, we divide 70 by the growth rate (r).
The number of years required for a specified population to double in size at the current rate of population growth.
Explanation of the Rule of 70
The formula is as follows: Take the number 70 and divide it by the growth rate. The result is the number of years required to double. For example, if your population is growing at 2%, divide 70 by 2. The result is 35; it will take 35 years for your population to double at a 2% growth rate.
Assuming long-term market returns stay more or less the same, the Rule of 72 tells us that you should be able to double your money every 7.2 years. So, after 7.2 years have passed, you'll have $200,000; after 14.4 years, $400,000; after 21.6 years, $800,000; and after 28.8 years, $1.6 million.
If you expect your wealth to grow by 12% a year, then it would take 6 years (72/12 = 6) to double.
7.1429 years or approximately 86 months.
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.
The value of $10,000 in 20 years depends on factors like inflation and investment returns. Assuming an average annual inflation rate of 2%, the future value of $10,000 would be approximately $6,730 in today's dollars. However, investing an average annual return of 7% could grow to around $38,697.
To use the Rule of 72 in order to determine the approximate length of time it will take for your money to double, simply divide 72 by the annual interest rate. For example, if the interest rate earned is 6%, it will take 12 years (72 divided by 6) for your money to double.
He has mentioned about rule of 72 which tells you that when you divide 72 with the rate of annual interest, the result will give you the no. of years in which your investment will be doubles.
If you deposited $10,000 into a savings account that earns a highly competitive APY of 4.85 percent and left that money untouched, you'd earn around $485 in a year if the rate remains unchanged.