6 simple ways to double your money over time
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Doubling your money sounds great in theory, but how do you actually make it happen? If you're saving for a big family goal or helping your teen learn the ropes of investing, it's not about flashy tricks or overnight wins. It's about steady, smart moves that work together over time. In this guide, we’ll break down a few tried-and-true strategies, and show how they fit together to help you learn how you can double your money over time.
Start with the Rule of 72
Let’s begin with a principle that makes the whole concept easier to grasp: the Rule of 72. This simple formula helps you estimate how long it will take for your money to double based on your interest or return rate.
Here’s how it works: Divide 72 by the rate of return you expect to earn. That number tells you approximately how many years it will take to double your money.
Example: If your investment earns 6% annually, 72 ÷ 6 = 12 years to double.
Why it matters: Understanding the Rule of 72 helps you compare growth options. Whether you're saving in a bank account, contributing to a retirement plan, or investing in the market, this gives you a framework to evaluate how fast your money might grow.
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Use tax-advantaged accounts wisely
One of the most effective ways to double your money over time is to reduce how much of it gets eaten away by taxes. That’s where Roth IRAs and 401(k)s come in.
These are special types of accounts designed to help you save for retirement. Here’s the key: the accounts themselves don’t grow, it’s what’s inside them that does. You can hold investments like ETFs or index funds inside these accounts, and depending on the type, your money either grows tax-deferred (401(k)) or tax-free (Roth IRA).
Think of them as a growth container that shields your money from taxes. The less you lose to taxes, the faster your money can grow and potentially double.
If you’re teaching your teen about saving for the long-term, it’s a great opportunity to explain how these accounts work and how getting an early start can make a big difference.
Invest in ETFs and index funds
So, what goes inside those accounts? Exchange-traded funds (ETFs) and index funds are great beginner-friendly options. They allow you to invest in a wide range of companies all at once, which helps lower risk.
Historically, the stock market has averaged about 7% annual returns after inflation. Using the Rule of 72, a 7% return means your money could double in about 10 years. That’s a powerful tool to build long-term wealth, especially when combined with the tax advantages above.
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Pay off high-interest debt
High-interest debt can undo your progress before it starts. For example, if you're paying 20% interest on a credit card, you're essentially losing 20% each year, which is much more than most investments earn.
Paying off that debt is like getting a guaranteed return. It's one of the fastest ways to strengthen your financial foundation so you can start building toward real growth.
Automate your savings
Consistency beats intensity. Automating your savings is like putting your money on autopilot. Whether you’re setting aside $10 a week or $100 a month, doing it automatically means you won’t forget or feel tempted to spend it.
Over time, automated savings helps you build the seed money that can later be invested or used to pay off debt. It creates the habit of saving, which is the first step toward financial growth.
💡 With Greenlight, families can set up automatic transfers to savings goals, track progress, and build strong habits early.
Increase your income (and reinvest it)
Sometimes, the best way to double your money is to increase how much you bring in. That’s where a side hustle could come in.
Whether it's a part-time gig, tutoring, or launching a small business, extra income gives you more to work with. And if you reinvest that money—into paying off debt, contributing to an investment account, or even boosting emergency savings—you’re accelerating your path to doubling your money.
For teens, it could mean mowing lawns or babysitting. For parents, maybe it’s freelancing or selling unused items. The goal is to earn more and to use that money wisely.
How it all fits together
To double your money, you need a few key ingredients working together:
Understanding the Rule of 72 helps to give you a realistic timeline.
Using tax-advantaged accounts helps you keep more of your gains.
Investing in diversified options like ETFs can offer long-term growth.
Paying off high-interest debt helps protect your progress.
Automating your savings builds discipline.
Earning more and reinvesting gives you extra fuel.
None of these are shortcuts. But when you combine them, they can create a strong, realistic path toward doubling your money over time. And the earlier your family starts, the more those habits can grow.
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This blog post is provided "as is" and should not be relied upon as a substitute for professional advice. Some content in this post may have been created using artificial intelligence; however, every blog post is reviewed by at least two human editors.
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