Compound Interest Calculator — future value
See how savings grow with compound interest and regular contributions, with a breakdown — in your browser.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
For estimation only — not financial advice.
About this tool
Use this compound interest calculator to see how a starting balance and regular deposits can grow over time as interest earns further interest. Enter your initial amount, an annual rate, how often interest compounds and any monthly or yearly contribution, and it projects the future value with a year-by-year breakdown of principal versus interest earned. It suits anyone planning long-term savings, a pension or an investment. All projections are computed in your browser, so none of your figures are uploaded or stored.
Frequently asked questions
What does compounding frequency change?
Compounding frequency is how often earned interest is added back to the balance so it can earn more. The future value follows A = P(1 + r/m)^(m·t), where m is the number of compounding periods per year. Daily or monthly compounding grows a little faster than annual at the same nominal rate, though the gap is usually small. Adding regular contributions, which this tool also models, makes a far bigger difference over time.
Will my savings really grow this much?
Probably not exactly. The projection assumes a single, steady interest rate for the whole period, while real returns rise and fall and may carry fees or tax on the interest. Inflation also reduces what the final figure can buy. See the result as a general illustration for learning and planning, not financial advice, and confirm the actual terms with your bank or provider.
Is my financial data sent anywhere?
No. Every figure is calculated on your own device by code running in the browser, so the amounts, rate and contributions you enter are never transmitted to or saved on a server. Nothing about your savings plan is logged, which means you can model as many different scenarios as you like, completely privately.