Most compound interest calculators only handle a single lump sum sitting untouched for years. That's rarely how real investing works — most people also add money regularly. Our compound interest calculator handles both at once: a starting amount plus ongoing monthly contributions, projected forward at your chosen rate.
What "Free" Actually Means Here
- No account, no email, no login wall
- Results update live as you type
- Runs entirely in your browser — your numbers never get sent anywhere or stored on a server
- Works on desktop, tablet, or phone without an app
A Worked Example
Start with $10,000, add $500 every month, at a 6% annual return, for 10 years:
- Total contributed = $10,000 + ($500 × 120 months) = $70,000
- Future value = $100,133.64
- Total interest earned = $30,133.64
Nearly $30,000 of that final balance came purely from compounding — money the account earned on its own, not money that was ever deposited.
Also Adjusts for Inflation
A future dollar amount only means something once you know what it can actually buy. Adding a 3% inflation assumption to the same example shows a real (inflation-adjusted) value of about $74,508.83 in today's purchasing power — a reminder that the nominal number on the screen and what it will actually be worth are two different things.
Project your own contributions and returns instantly
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