Compound interest calculator. Watch savings snowball.
Enter a principal, rate and time horizon — get future value, total contributions, interest earned, a year-by-year table and a growth chart. Everything is computed in your browser, nothing uploaded.
A free online tool by Digital HeroesWhat you start with today.
Added at the end of each period.
How often interest is added back to the balance.
Calculated locally — nothing is sent anywhere.
Year-by-year breakdown
| Year | Start balance | Contributions | Interest | End balance |
|---|
The eighth wonder of the world
Compound interest pays you on your interest, so balances accelerate the longer you leave them. Time and consistency usually matter more than a high rate — small monthly contributions started early often beat larger sums started late. Every figure here is computed in your browser, so your numbers stay private. Planning something bigger? Book a call with Digital Heroes.
Everything a projection should show.
- Project a lump-sum investment over any horizon up to 100 years — including fractional years — at a chosen annual rate.
- Add monthly or yearly contributions and see how consistent saving accelerates growth against interest alone.
- Compare compounding frequencies — monthly, quarterly or annual — and watch the end balance shift instantly.
- Read the year-by-year table: start balance, contributions, interest earned and end balance for every year, partial final year included.
- Export the full schedule as CSV for a spreadsheet or financial model, and read the money-multiple at a glance.
- Switch currency symbols (USD, EUR, GBP, INR, JPY, AUD, CAD or none) to match your region.
Five steps, no manual.
- Enter your initial principal — the amount you have today — and an annual interest rate.
- Set a time horizon in years and, optionally, a regular contribution per month or per year.
- Choose a compounding frequency (monthly, quarterly or annually) that matches your account.
- Results update instantly as you type — future value, total contributions, interest earned and the growth chart.
- Scroll to the year-by-year table or click Export CSV to save the full schedule.
Frequently asked questions.
Is the Compound Interest Calculator free?
Is it private? Are my numbers uploaded anywhere?
Does it work offline?
How is compound interest calculated here?
Can I export the year-by-year schedule?
Published · Last updated .
