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 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.
What interest rate will double every 7 years? ›
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).
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.
Is 7% annual return realistic? ›
In short, the average stock market return since the S&P 500's inception in 1926 through 2018 is approximately 10-11%. When adjusted for inflation, it's closer to about 7%. [Since we're talking citations in this post: Investopedia.]
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.
Can I double my money in 5 years? ›
As a rate of return, long-term mutual funds can offer rates between 12% and 15% per year. With these mutual funds, it may take between 5 and 6 years to double your money.
How long will it take $1000 to double at 6 interest? ›
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.
How to double $10,000? ›
Here are some ways to flip $10,000 fast:
- Flip items (buy low, sell high)
- Start a blog.
- Start an online business.
- Write an email newsletter.
- Create online courses or teach online.
- Invest in real estate with EquityMultiple.
It will take approximately 15.27 years to increase the $2,200 investment to $10,000 at an annual interest rate of 6.5%.
“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 will 50k be worth in 20 years? ›
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.
How much do I need in a 401k to get $2 000 a month? ›
With the $1,000 per month rule, if you plan to withdraw 5% of your savings each year, you'll need at least $240,000 in savings. If you aim to take out $2,000 every month at a withdrawal rate of 5%, you'll need to set aside $480,000. For $3,000, you would aim to save $720,000.
How much money do I need to invest to make $1000 a month? ›
A stock portfolio focused on dividends can generate $1,000 per month or more in perpetual passive income, Mircea Iosif wrote on Medium. “For example, at a 4% dividend yield, you would need a portfolio worth $300,000.
How much money do I need to invest to make $3,000 a month? ›
Imagine you wish to amass $3000 monthly from your investments, amounting to $36,000 annually. If you park your funds in a savings account offering a 2% annual interest rate, you'd need to inject roughly $1.8 million into the account.
What is 7 year gift inheritance? ›
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.
Why do investments double every 7 years? ›
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.
How much money can be gifted per year? ›
The IRS allows every taxpayer is gift up to $18,000 to an individual recipient in one year. There is no limit to the number of recipients you can give a gift to.
How to become financially independent in 7 years? ›
- Set Life Goals.
- Make a Monthly Budget.
- Pay off Credit Cards in Full.
- Create Automatic Savings.
- Start Investing Now.
- Watch Your Credit Score.
- Negotiate for Goods and Services.
- Get Educated on Financial Issues.
