Free Investing Calculator Tool

Starting Amount
Additional Contribution
Contribution Frequency
Expected Rate of Return
Years to Grow

This investment will be worth
Year Starting Amount Annual Contribution Total Contribution Interest Earned Total Interest Earned End Balance

Calculator Definitions

  • Starting Amount: The total amount of all of your investment accounts combined. This may include your 401(k), IRA, or other investment accounts.
  • Additional Contribution: How much you plan on investing on a regular basis. This includes contributions across all investment accounts.
  • Contribution Frequency: How often you plan on investing the additional contributions. This may be annually, semi-annually, monthly, weekly, or biweekly.
  • Expected Rate of Return: The average annual rate of return you expect from all of your investments. For example, if you are investing in just an S&P 500 index fund, you might expect a 8% annual return.
  • Years to Grow: How long you want to calculate your investment growth.
  • Total Contributions: The total amount you invest over the specified ‘Years to Grow’ timeline. For example, if you invest $100 per month for 30 years, your total contributions would be $36,000.
  • Total Interest Earned: The total amount of interest earned over your specified ‘Years to Grow’ timeline. Interest is compounded annually for this calculator, although some of your own investments may compound monthly.
 

How To Use the Investing Calculator (Step By Step)

Here's how to calculate how much your investments can grow over the next 10, 20, 30 years or more.

1. Total up your investments

Add up the total of all your investments across all investment accounts. This may include your Roth IRA, 401(k), HSA, brokerage, or other accounts.

This total is your ‘Starting Amount.’

2. Figure out how much you can invest

Decide how much you can invest on a regular basis. The best way to do this is to create a budget and make a plan to set aside money for investing each month.

Let’s say you can invest $100 per paycheck and are paid every other week — you’d then be able to set your ‘Contribution Amount’ to $100 and ‘Contribution Frequency’ to biweekly.

3. Determine your investment rate of return

To calculate your future investment growth, you’ll need to know how much your investments will return. While past performance isn’t a predictor of future results, they can help indicate how much you can expect when investing in broad-based funds.

For example, the S&P 500 has returned 8% to 10% per year over the last 100 years — so if you plan on investing in just an S&P 500 index fund, you can input 8% to 10% returns under ‘Expected Rate of Return.’

4. Choose how long you want to invest

Choose how long you plan on investing. For example, if you want to see your investment growth in 20 years, enter the number 20 in the ‘Years to Grow’ input.

Hit the ‘Calculate’ button to run your investment calculation.

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Investment Calculator Example

Let’s say you want to figure out how much you need to invest to get to $100,000.

You currently have $5,000 invested in your employer’s 401(k) account and have decided to invest $200 per paycheck.

You get paid biweekly and set up your 401(k) contributions to make sure you are investing $200 straight from your paycheck. You decide to invest in an S&P 500 index fund inside your 401(k) account and expect an 8% annual return.

Finally, you want to get to $100,000 in the next 15 years, so you set your ‘Years to Grow’ number to 15. Here’s what your results look like:

If you continue to invest $200 per paycheck and get an annual return of 8% per year, your investments will grow to over $166,000 in the next 15 years. And over that 15-year period of time, you’ll earn over $83,000 in interest alone!

You can hover over the investment calculator graph to see that you’ll hit a milestone of $100,000 in 2034 if you start investing in 2024.

What To Consider When Using the Investing Calculator

While it’s easy to run a few example scenarios and see how your investments might grow in the future, here are a few things to keep in mind:

Investment returns are not guaranteed

Investing involves risk, and one of those risks includes the risk of loss.

While an investment calculator may show how your investments could grow, it’s usually not the same growth each year. In fact, some years you might lose money — so make sure to account for that when planning your investment strategy.

Diversity is important

Investing in a single stock or asset is the equivalent of putting all your eggs in one basket.

Instead, invest in index funds that hold hundreds (or thousands) of investments to lower your risk and diversify your portfolio.

Automation is key

When investing, it’s important to have a “set it and forget it” approach. Automating your contributions helps you invest regularly without even thinking about it.

This helps you keep emotion out of your investment strategy and build your wealth steadily over time.

The calculator can’t invest for you

While this calculator is a great starting point to see how your investments can grow, it can’t invest for you.

You have to choose to enroll in your 401(k) at work, or open a Roth IRA, or open a brokerage account. You have to transfer money over to your investment account and choose what to invest in.

Those actions are what make this calculator real in your life instead of just numbers on a screen.

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