The Rule of 72 | Primerica (2024)

FAQs

The Rule of 72 | Primerica? ›

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. As you can see, a one-time contribution of $10,000 doubles six more times at 12 percent than at 3 percent.

The Rule of 72 is derived from a more complex calculation and is an approximation, and therefore it isn't perfectly accurate. The most accurate results from the Rule of 72 are based at the 8 percent interest rate, and the farther from 8 percent you go in either direction, the less precise the results will be.

The Rule of 72 is not precise, but is a quick way to get a useful ballpark figure. For investments without a fixed rate of return, you can instead divide 72 by the number of years you hope it will take to double your money. This will give you an estimate of the annual rate of return you'll need to achieve that goal.

Advantages and Disadvantages of Rule of 72

However, the Rule of 72 is based on a few assumptions that may not always be accurate, such as a constant rate of return and compounding period. It also does not take into account taxes, inflation, and other factors that may impact investment returns.

The Rule of 72 is a convenient method to estimate the approximate time for invested capital to double in value. By merely taking the number 72 and dividing it by the rate of return (or interest rate) expected to be earned, the output is the approximate number of years for an investment to double.

The Rule of 72 helps you determine how long it might take for your money to hypothetically double. It's worth noting, the “rule of 72” definition isn't necessarily perfectly accurate because past market results do not predict future market behavior.

The Rule of 72 will not work if the rate of interest fluctuates or is reset after a specific period. Moreover, the Rule of 72 works better with a lower rate of interest when compared to a higher rate of interest.

One of the easiest ways to double $1,000 is to invest it in a 401(k) and get the employer match. For example, if your employer matches your contributions dollar for dollar, you'll get a $1,000 match on your $1,000 contribution.

The most basic example of the Rule of 72 is one we can do without a calculator: Given a 10% annual rate of return, how long will it take for your money to double? Take 72 and divide it by 10 and you get 7.2. This means, at a 10% fixed annual rate of return, your money doubles every 7 years.

What is the math behind the Rule of 72? ›

The rule is this: the time taken for an amount of money to double for any interest rate is approximately 72/(interest rate).

Albert Einstein often gets credit, but Italian mathematician Luca Pacioli most likely invented, or introduced the Rule of 72 to the popular world in the late 1400s.

The Rule of 78 is an important consideration for borrowers who potentially intend to pay off their loans early. The Rule of 78 holds that the borrower must pay a greater portion of the interest rate in the earlier part of the loan cycle, which means the borrower will pay more than they would with a regular loan.

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 turn $5,000 into more money, explore various investment avenues like the stock market, real estate or a high-yield savings account for lower-risk growth. Investing in a small business or startup could also provide significant returns if the business is successful.

This shows that the rule of 72 is most accurate for periodically compounded interests around 8%. Similarly, replacing the "R" in R/200 on the third line with 2.02 gives 70 on the numerator, showing the rule of 70 is most accurate for periodically compounded interests around 2%.

The rule of 72 can help you get a rough estimate of how long it will take you to double your money at a fixed annual interest rate. If you have an average rate of return and a current balance, you can project how long your investments will take to double.

What is the difference between Rule 72 and Rule 69? The main difference is that Rule of 72 considers simple compounding interest, whereas Rule of 69 considers continuous compounding interest. Additionally, the accuracy of Rule of 72 decreases with higher interest rates.

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%.