Enter an initial investment. If you have, say, $1,000 to invest right now, include that amount here. If you don’t have an initial amount to invest now, you can enter $0.

Enter your regular contributions. If you plan to invest a certain amount every month into your investment account (a strategy known as dollar-cost averaging), include this amount after selecting the “monthly” option. Or, if you’d rather invest one lump sum once per year, choose “annually” and include your planned annual contribution. If you do not plan to make regular contributions, select either option and enter $0.

Choose how long your investment will grow. How long do you plan to keep your money invested? If you’re investing in stocks, it’s generally a good idea to stay invested for at least five years to weather any volatility post-purchase.

Enter your expected rate of return. For a point of reference, the S&P 500 has a historical average annual total return of about 10%, not accounting for inflation. This doesn’t mean you can expect 10% growth every year; you could experience a gain one year and a loss the next. But if you keep your money invested for the long term, the goal is for these gains and losses to average out over time, ideally ending significantly in the black by the end of the investment period. We've added a default return of 6%, which is fairly conservative — feel free to adjust it to match your expectations for your own investment portfolio.

Enter how frequently you want your investment returns to compound. You can opt to match the compounding frequency to your contribution frequency — meaning, if you plan to make additional contributions on a monthly basis, you'd choose monthly compounding. If you plan to make annual contributions, you might opt for annual compounding. But daily compounding is likely to get you closest to estimating typical investment performance. Compounding at more frequent intervals leads to higher growth over time.