Compound Interest Calculator
Calculate how an investment grows over time with compound interest. Set your principal, rate, term, and compounding frequency, free and private, right in your browser.
Enter a starting balance, a rate, and how often it compounds to see exactly how your money grows year over year, useful for comparing savings accounts, projecting an investment, or checking how much a recurring contribution schedule adds up to over time.
How to use it
- Enter your starting balance and interest rate
- Set the compounding frequency and time period (add optional recurring contributions)
- View the year-by-year growth table and final total
Frequently asked questions
- What's the difference between compounding monthly vs. annually?
- More frequent compounding earns slightly more because interest starts earning its own interest sooner. On a typical savings rate, monthly vs. annual compounding usually only differs by a small fraction of a percent in the final balance, but the tool lets you compare both side by side so you can see the exact numbers for your rate.
- Can I include regular deposits, not just a lump sum?
- Yes. Add a recurring contribution amount (like $100/month) and it gets added on top of the compounding growth, so you can model a real savings plan rather than just a one-time investment.
- Does this account for inflation or taxes?
- No, it shows nominal growth based on the rate you enter. If you want a real (inflation-adjusted) result, subtract your expected inflation rate from the interest rate before entering it.
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Nothing is uploaded
The file never leaves your device. There is no server to send it to, so there is nothing to leak, log, or subpoena.
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No signup, no limits
No account, no email, no daily cap, no watermark, and no paid tier waiting behind the third file.
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Works offline
Load the page once and it keeps working with the network off, because all the work was always happening locally.