The Rule of 72, Doubling Your Money, and Investment Returns (2024)

FAQs

The Rule of 72, Doubling Your Money, and Investment Returns? ›

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. In this case, 18 years.

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.

To find out how many years it would take for a $100 investment to double at this interest rate, we divide 72 by 6.25. 72 ÷ 6.25 = 11.52 Therefore, it would take approximately 11.52 years for a $100 investment to double when the interest rate is 6.25 percent per year.

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 (1.10^7.3 = 2). The Rule of 72 is reasonably accurate for low rates of return.

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 formula for the Rule of 72 is ridiculously simple. You divide 72 by the annual rate of return you expect to earn on that investment. For example, if you expect an annual return of 8%, it would take approximately 9 years for your investment to double (72 divided by 8 equals 9).

Errors and Adjustments

The rule of 72 is only an approximation that is accurate for a range of interest rate (from 6% to 10%). Outside that range the error will vary from 2.4% to 14.0%. It turns out that for every three percentage points away from 8% the value 72 could be adjusted by 1.

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 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. In this case, 18 years.

Final answer:

It will take approximately 15.27 years to increase the $2,200 investment to $10,000 at an annual interest rate of 6.5%.

How to double $2000 dollars in 24 hours? ›

Try Flipping Things

Another way to double your $2,000 in 24 hours is by flipping items. This method involves buying items at a lower price and selling them for a profit. You can start by looking for items that are in high demand or have a high resale value. One popular option is to start a retail arbitrage business.

1 At 10%, you could double your initial investment every seven years (72 divided by 10). In a less-risky investment such as bonds, which have averaged a return of about 5% to 6% over the same period, you could expect to double your money in about 12 years (72 divided by 6).

The rule of 72 is a formula that lets you get a close approximation of how long it would take for an investment to double considering its set rate of return, an estimation that factors compound interest in without requiring you to do the more complex math required in calculating compound interest.

It's called the Rule of 72. The principle is simple. Divide 72 by the annual rate of return to figure how long it will take to double your money. For example, if you earn an 8 percent annual return, it will take about 9 years to double.

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.

Diversifying Your Portfolio to Reach a 10% Return

A diverse portfolio could consist of 30% in a mix of value and growth stocks, 30% in index funds, 20% in bonds, 10% in real estate and 10% in alternative investments like P2P lending or commodities.

If your money is in a savings account earning 3% a year, it will take 24 years to double your money (72 / 3 = 24).

Very few investors know how long it takes to double their money. Rule of 72 can be of help. Divide 72 by the expected rate of return and the answer is the number of years required to double your money. For example, if a bond offers 6 percent rate of interest per year, then you will double your money in 12 years.