Investing is a long game, measured in years. Understanding your return on investment (ROI) can help you achieve your goals. It all depends on your rate of return, your time horizon, taxes and a host of other factors. Use Low Cost Advisor’s return on investment calculator to help plan your long-term investing strategy.

ROI Calculator

Below you’ll find our ROI calculator as well as explanations of the data required. Jump to the bottom for information on how to use the calculator and answers to frequently asked questions.

How to Use Our ROI Calculator

To get the most out of this ROI calculator, you’ll want to change the default inputs to reflect your financial situation and goals. Here are a few tips for some of the more complex fields in the calculator.

Use a Realistic Inflation Rate

Inflation is how much prices rise across the economy, eroding the purchasing power of your dollars over time. When you invest, you’re probably doing so at least in part to beat inflation and earn returns that help you maintain and grow your wealth.

The 2.9% default figure on this calculator is actually a pretty good average inflation estimate, and you might consider leaving it. Between 1925 to 2020, the Consumer Price Index (CPI), a common measure of U.S. inflation, rose 2.9% per year, on average. Just beware that some years see substantially more inflation, like 1980’s sky-high 13.5% rate.

Read more: Why Is Inflation Rising Right Now?

Input Your Income Tax Rate

This is the percentage of your income that goes to taxes each year. If you aren’t sure what tax bracket you’re in, you can find the federal guidelines here.

Keep in mind that for the sake of simplicity, this calculator assumes that you cash out your gains each year, creating taxable events that you must pay out at your current income tax rate.
Most investors, however, are investing for the long term and won’t realize these gains every year. This allows them to benefit from lower long-term capital gains tax rates when they hold their investments for at least a year.

Consider Adjusting Your Contributions for Inflation

To keep the effective value of your contribution consistent across the years, you may want to check the “Inflation Adjustment” box.

This will update your annual contributions to keep track with rising inflation, and it may help you paint a more realistic picture of your future investment’s worth. It’s also a valuable reminder that your investment contribution rate shouldn’t be static—you should revisit it each year to make sure you’re putting away enough to meet your goals.

Look at the Calculator Values after Inflation

Whatever your investment goal might be, you probably know the cost of the thing today. But you might be less familiar with how much your goal may cost you after years or decades of inflation.

That’s why it’s helpful to check the “Show Values After Inflation” box. This will show you if by your end date you would have enough purchasing power to accomplish your goal based on today’s prices. If the answer is no, you may want to adjust your contribution rate.

Compare Simple vs Compound Interest

Compound interest is the engine that powers your investment returns over time. With compound interest, the amount you earn each year grows can be reinvested in your account to help you earn more.

Here’s how that can work: Say you have $1,000 to invest and you expect to earn 10% returns on it each year. The first year you earn $100. But the next year you earn $110, to reflect your investment account’s new base balance of $1,100. Over 10 years, you’d accrue almost $2,600.

Simple interest is different. With simple interest, your returns are always based on the starting balance of your account. This is essentially assuming you took out your profits every year and spent them, which you might do under certain circumstances, like if you were investing for income in retirement. Otherwise, you’ll probably want to avoid this situation as it can drastically undercut your returns.

Continuing the example from above, with simple interest, you’d wind up with about $600 less than if you invested with compound interest after 10 years. That’s because every year, you’re earning the same $100 that you did the first year.

Positioning yourself to benefit from compound interest is why it’s important to leave your money alone once it’s invested.

Return on Investment Calculator FAQs