Whether you want to evaluate offers that promise to "double your money fast" or establish investment goals for your portfolio, a quick-and-dirty method will show you how long it will take to double your money. It's called the Rule of 72 and can be applied to any investment.
How the Rule Works
To use the Rule of 72, divide the number 72 by an investment's expected annual return. The result is the number of years it will take, roughly, to double your money. For example, if the expected annual return of a bank Certificate of Deposit (CD) is 2.35% and you have $1,000 to invest, it will take 72/2.35 or 30.64 years for you to double your original investment to $2,000. If the expected annual return on a CD is 5% and you invest the same amount, it will take you 14.4 years to double your money.
CDs are great for safety and liquidity, but let's look at stocks. It's impossible to know in advance what will happen to stock prices. We know that past performance does not guarantee future returns. But by examining historical data, we can make an educated guess. According to Standard and Poor's, the average annualized return of the S&P index, which later became the S&P 500, from 1926 to 2020 was 10%. 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).
Keep in mind that we're talking about annualized returns or long-term averages. In any given year, stocks might return 25% or lose 30%. Over a long period, the returns will average out to 10%. The Rule of 72 doesn't mean that you'll be able to take your money out of the stock market in 10 years. You might have doubled your money by then, but the market could be down, and you might have to leave your money in for several more years until things turn around. If you must achieve a certain goal or be able to withdraw your money by a certain time, the Rule of 72 isn't enough. You'll have to plan carefully, choose your investments wisely, and keep an eye on your portfolio.
Achieving Your Investment Goals
A professional financial advisor may be your best bet for achieving specific investing goals, but the Rule of 72 can help you get started. If you know that you need to have a certain amount of money by a certain date, for example, for retirement or to pay for your newborn child's college tuition, the Rule of 72 can give you a general idea of which asset classes you'll need to invest in to achieve your goal.
First, you can use the Rule of 72 to determine how much college might cost in 18 years if tuition increases by an average of 4% per year. Divide 72 by 4% and you know that college costs are going to double every 18 years.
Right now you have $1,000 to invest and with an 18-year time horizon, you want to put it all in stocks. We saw in the previous section that investing in the S&P 500 has historically allowed investors to double their money about every six or seven years. Your initial $1,000 investment will grow to $2,000 by year 7, $4,000 by year 14, and $6,000 by year 18. Suddenly 18 years isn't as long a time horizon as you thought, perhaps leading you to rethink your investment strategy.
The Bottom Line
While the Rule of 72 is a good investment guideline, it only provides a framework. If you're looking for a more precise outcome, you'll need to better understand an asset's future value formula. The Rule of 72 also does not take into account the effect of investment fees, such as management fees and trading commissions, can have on your returns. Nor does it account for the losses you'll incur from any taxes you have to pay on your investment gains.
FAQs
You would need to earn 10% per year to double your money in a little over seven years.
What is the 7 year money rule? ›
How the Rule Works. To use the Rule of 72, divide the number 72 by an investment's expected annual return. The result is the number of years it will take, roughly, to double your money.
What is the quickest way to double your money? ›
The classic approach of doubling your money by investing in a diversified portfolio of stocks and bonds is probably the one that applies to most investors. Investing to double your money can be done safely over several years, but for those who are impatient, there's more of a risk of losing most or all of their money.
Does a 401k double every 7 years? ›
One of those tools is known as the Rule 72. For example, let's say you have saved $50,000 and your 401(k) holdings historically has a rate of return of 8%. 72 divided by 8 equals 9 years until your investment is estimated to double to $100,000.
What is the rule of 7 doubling your money? ›
According to this rule, if you divide 7 by the annual rate of return, the result will indicate the approximate number of years it would take for the investment to double.
Will my money double in 7 years? ›
All you do is divide 72 by the fixed rate of return to get the number of years it will take for your initial investment to double. You would need to earn 10% per year to double your money in a little over seven years.
How many years does it take to double your money at 7%? ›
If you earn 7%, your money will double in a little over 10 years. You can also use the Rule of 72 to plug in interest rates from credit card debt, a car loan, home mortgage, or student loan to figure out how many years it'll take your money to double for someone else.
How to double $1,000 dollars? ›
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.
How do you flip money ASAP? ›
How To Flip Money To Make More Money?
- Buy And Sell Products On eBay. ...
- Become A Local Real Estate Flipper. ...
- Invest In Commodities. ...
- Trade Forex. ...
- Flip Cars For Profit. ...
- Invest In Mutual Funds. ...
- Buy & Sell Domain Names. ...
- Buy & Sell Antiques.
How can you make $5,000 turn into $10,000? Turning $5,000 into $10,000 involves investing in avenues with the potential for high returns, such as stocks, ETFs or real estate. Another approach is to use the money as seed capital for a profitable small business or side hustle.
Assuming an annual return rate of 7%, investing $50,000 for 20 years can lead to a substantial increase in wealth. If you invest the money in a diversified portfolio of stocks, bonds, and other securities, you could potentially earn a return of $159,411.11 after 20 years.
What age should you have 100k in 401k? ›
“By the time you hit 33 years old, you should have $100,000 saved somewhere,” he said, urging viewers that they can accomplish this goal. “Save 20 percent of your paycheck and let the market grow at 5% to 7% per year,” O'Leary said in the video.
What is the 5 year rule for 401k? ›
Contributions and earnings in a Roth 401(k) can be withdrawn without paying taxes and penalties if you are at least 59½ and had your account for at least five years. Withdrawals can be made without penalty if you become disabled or by a beneficiary after your death.
What is the magic number to double your money? ›
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.
What is the rule number 1 of money? ›
Warren Buffett once said, “The first rule of an investment is don't lose [money]. And the second rule of an investment is don't forget the first rule. And that's all the rules there are.”
Is 7% annual return realistic? ›
He said a more reasonable return assumption is 5% for a balanced portfolio of stocks and bonds or 7% for a more aggressive exposure to stocks.
Does the S&P 500 double every 7 years? ›
According to his math, since 1949 S&P 500 investments have doubled ten times, or an average of about seven years each time. In some cases, like 1952 to 1955 or 1995 to 1998, the value of the investment doubled in only three years.
Does the 7 year rule apply? ›
After 7 years, the gift does not count towards the value of your estate, which is known as “the 7-year rule” for inheritance tax purposes. This rule is why, very often, parents will give their children or grandchildren gifts long before they believe they will pass away, in order to avoid paying tax on the gift.
How much money can be gifted per year? ›
Under the current rules, you can give up to $18,000 to any individual in one year—and to as many people as you choose. This is an annual limit. You can give up to $18,000 to as many individuals as you choose every year without owing a gift tax.
