Rule of 72 Calculator By Years (2024)

FAQs

What is the Rule of 72 answer? ›

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.

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).

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. This calculator flips the 72 rule and shows what interest rate you would need to double your investment in a set number of years.

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.

For higher rates, a larger numerator would be better (e.g., for 20%, using 76 to get 3.8 years would be only about 0.002 off, where using 72 to get 3.6 would be about 0.2 off). This is because, as above, the rule of 72 is only an approximation that is accurate for interest rates from 6% to 10%.

A borrower who pays 12% interest on their credit card (or any other form of loan that is charging compound interest) will double the amount they owe in six years.

If you want to double it in five years, the portfolio should be invested such that it yields 72/5=14.4%. 5. Though the Rule of 72 isn't the most accurate calculation, it gives a good idea to investors to project their portfolio values.

Summary: An investment of $10000 today invested at 6% for five years at simple interest will be $13,000.

How long will it take for you to get $100000.00 if you invest $5000.00 in an account giving you 9.7% interest compounded continuously? ›

t = ln(100,000/5,000)/0.097 ≈ 12.35 years Using the formula for continuous compounding interest, it will take approximately 12.35 years for a $5,000 investment to grow to $100,000 at an interest rate of 9.7% compounded continuously.

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%.

The rule of 8-4-3 when it comes to compounding indicates a style of investment that accelerates growth with time. Initially, a corpus doubles within 8 years through an average annual return of 12% subsequently another doubling happens for the same period after another 4 years following its initial setting up.

Rule of 72 Formula

Commonly, periods are years so R is the interest rate per year and t is the number of years. You can calculate the number of years to double your investment at some known interest rate by solving for t: t = 72 ÷ R.

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.

You can also apply the Rule of 72 to debt for a sobering look at the impact of carrying a credit card balance. Assume a credit card balance of $10,000 at an interest rate of 17%. If you don't pay down the balance, the debt will double to $20,000 in approximately 4 years and 3 months.

The Rule of 70, while generally more accurate, is less convenient for mental calculations due to the indivisibility of 70 by common numbers such as 3, 4, 6, 8, 9, or 12. Conversely, the Rule of 72, being divisible by those numbers, is often preferred for its ease of use despite being slightly less accurate.

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.