purr.tools

Investment Calculator

Enter your investment details to see how your money grows over time.

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How to use the investment calculator

Enter the initial amount, any monthly contributions, the expected annual return rate, and the number of years. The calculator compounds monthly and shows the final balance broken down into contributions and growth.

Compound interest reference

At 7% annual return: $10,000 becomes ~$19,672 after 10 years with no contributions. At 10%: ~$25,937. Adding $200/month at 7% for 10 years yields ~$53,500 total.

Frequently Asked Questions

Does this assume compound interest?

Yes, returns are compounded monthly, which is the standard assumption for most investment accounts.

What return rate should I use?

A common benchmark is 7% for a diversified stock index fund (long-run US market average after inflation). Adjust to match your own investment's expected return.

Embed this tool

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<iframe
  src="https://purr.tools/en/embed/investment-calculator"
  width="100%"
  height="500"
  style="border:0;border-radius:8px;"
  loading="lazy"
  title="Investment Calculator -- Free Online Tool"
  allow="clipboard-write"
></iframe>