Compound Interest Calculator
See what savings or investments grow to over time, with or without regular monthly contributions. The calculator separates what you put in from what the interest earned, which is the number that actually shows compounding at work — and it handles yearly through daily compounding, since the frequency changes the result more than most people expect.
Final balance
$20,096.61
- Total you put in
- $10,000.00
- Interest earned
- $10,096.61
- Growth
- 100.97%
Figures are before inflation, tax and fees, all of which reduce the real return.
Nothing is uploaded — this tool runs inside your browser, so your files never leave your device.
Why use this tool
- Optional monthly contributions, each grown for the time it's actually invested
- Yearly, half-yearly, quarterly, monthly or daily compounding
- Separates the money you contributed from the interest earned
- Runs in your browser — no sign-up, no data captured
How it works
- 1Enter your starting amount and anything you add monthly.
- 2Set the interest rate, the number of years, and how often it compounds.
- 3Compare 'total you put in' against 'interest earned' to see compounding working.
Compound Interest Calculator — frequently asked questions
Interest is added to your balance, and the next round of interest is calculated on that larger balance. Over short periods the effect is small; over decades it dominates, which is why the interest earned can exceed everything you contributed.
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