What is compounding?

Compounding is one of the most important terms for beginning investors to understand. It’s a way to potentially increase your savings, just by staying invested in the market.

In simplest terms, compounding is any return earned on your principal, plus your past returns. For example, if you have money in a bank account, it’s the interest on that sum plus the past interest it has earned over time. If you have money in an investment account, it’s the percentage you may earn on top of your original investment, plus its previous earnings.

Good to know: Principal is the original sum of money you put into an investment. Interest and earnings—the percentage you earn on your principal—can be calculated on a daily, monthly, quarterly, or annual basis.

How does compounding work?

Imagine that you deposited $100 in a savings account that accrues 10% interest annually. After one year, you’d have $110 in that savings account. After two years, though, your interest would have compounded, and you’d have $121.

That’s because you’re no longer earning 10% interest only on your initial deposit of $100 after one year—you’re earning 10% interest on $110. Keep in mind, however, that some experts currently predict that investing in almost anything will generate an annual return of less than 10% in the long run.

Note, however, that most banks don’t pay an interest rate as high as 10% on savings account deposits. The national average is only 0.09%, according to the FDIC. Also, interest isn’t always calculated on an annual basis—it’s sometimes calculated and compounded on a daily, monthly, or quarterly basis.

Year 1Year 2Year 3Year 4
Starting balance$100$110$121$133.10
+ 10% rate of return$10$11$12.10$15.31
Ending balance$110$121$133.10$146.41

*Example is a hypothetical illustration of mathematical principles, and is not a prediction or projection of performance of an investment or investment strategy.

And after 10 years of compounding at a rate of 10%, your $100 deposit would grow to $259.37. That’s the power of compounding in action.

*Example is a hypothetical illustration of mathematical principles, and is not a prediction or projection of performance of an investment or investment strategy. It assumes an initial $100 contribution and a 10% annual rate of return (compounded annually) and does not account for fees or taxes.

A compounding brain teaser

If you were offered the choice of $100,000 today, or a penny today, with the amount you receive doubled every day for a month (a penny on the first day, 2 cents on the second day, 4 cents on the third day, etc.), which would you choose?

Surprisingly, it’s actually smarter to start with the penny, because by day 31, you’d have more than $10 million.

The power of compounding…and automation

One of the keys to maximizing your financial potential is to save or invest money early, and often. Stash users can automate the process by enabling Auto-Stash tools, which can save or invest money automatically for you.

Turn on Auto-Stash

Auto-Stash is an easy-to-use tool available on the app that can help you save or invest small amounts of money consistently over time, regardless of market conditions. You won’t have to worry about trying to pick the right time to invest or “timing the market” which we don’t recommend.

Auto-Stash boasts a few key features that can help you supercharge your saving and investing, including Set Schedule, which allows you to set up automatic transfers.

You select the amount you want to set aside, when and how often you want to set it aside, and whether you’d like Stash to automatically invest it in your ETFs and stocks, or simply place the money in your cash account. It’s an easy way to save and invest regularly, on a schedule that works for you.

It can be a relatively easy way to help make sure compounding work for you!

Make saving and investing a habit.

Go automatic with Auto-Stash.

Start now

Make saving and investing a habit.

Go automatic with Auto-Stash.

Start now

Make saving and investing a habit.

Go automatic with Auto-Stash.

Start now