How fast can you double your money with PPF, MF, Bank FDs — Rule of 72 explains (2024)

FAQs

How long will it take to double your money using the Rule of 72? ›

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.

If the interest per quarter is 4% (but interest is only compounded annually), then it will take (72 / 4) = 18 quarters or 4.5 years to double the principal. If the population of a nation increases at the rate of 1% per month, it will double in 72 months, or six years.

Rule 72 is a method used to find the number of years an investment will take to double in value. In other words, this method is easy to calculate how long the invested amount will be doubled at a specific rate. This method provides an accurate measurement.

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.

The Rule of 72 is reasonably accurate for low rates of return. The chart below compares the numbers given by the Rule of 72 and the actual number of years it takes an investment to double. Notice that although it gives an estimate, the Rule of 72 is less precise as rates of return increase.

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.

That is accomplished by dividing 72 by the expected rate of return. For instance, at an annual compound rate of 6%, funds will double in 12 years. This being a formula, it works in the opposite direction, too: You can figure the compound rate of return required to double your money in a certain time frame.

Left click and hold on the bottom right corner of cell B2 and drag the cell down to cell B6. Now, use the rule of 72 to calculate the approximate number of years by entering "=72/A2" into cell C2, "=72/A3" into cell C3, "=72/A4" into cell C4, "=72/A5" into cell C5 and "=72/A6" into cell C6.

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.

It is not an exact value and can only provide a general estimate of the time required to double the investment. If the interest rate changes due to some factor, the Rule of 72 becomes null and void. The Rule of 72 does not apply to changing interest rate investments or basic interest investments.

Does Rule of 72 apply to Roth IRA? ›

The RMD rules apply to all employer sponsored retirement plans, including profit-sharing plans, 401(k) plans, 403(b) plans, and 457(b) plans. The RMD rules also apply to traditional IRAs and IRA-based plans such as SEPs, SARSEPs, and SIMPLE IRAs. The RMD rules do not apply to Roth IRAs while the owner is alive.

The rule says that to find the number of years required to double your money at a given interest rate, you just divide the interest rate into 72. For example, if you want to know how long it will take to double your money at eight percent interest, divide 8 into 72 and get 9 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%.

To find the approximate number of years needed to double an investment, divide 72 by the interest rate. In this case, with an interest rate of 6.25%, divide 72 by 6.25, which is approximately 11.52. Therefore, it would take approximately 11.52 years to double the $100 investment.

The Rule of 70 Formula

Hence, the doubling time is simply 70 divided by the constant annual growth rate. For instance, consider a quantity that grows consistently at 5% annually. According to the Rule of 70, it will take 14 years (70/5) for the quantity to double.

To calculate how long it takes money to double, divide the interest rate into 72. To see how long money triples, divide it into 115. Assuming a 7% interest rate, it will take approximately 10.3 years for the original principal to double and 16.4 years to triple. There is also a rule of 144.