Compound Interest Calculator
Estimate how a lump sum grows with annual compounding: the final value is the principal multiplied by (1 + annual rate) raised to the number of years. You get the balance, the interest earned and the multiple, with no fees or extra contributions.
- Enter the principal, the annual return in percent and the number of years.
- You get the final balance, the interest earned and the multiple, for example about 1.63× over 10 years at 5%.
- Run it again with 20 or 30 years to see how much time matters.
FAQ
Why is this lower than my bank app?
Interest compounds once a year here, with no added contributions. Many products compound monthly or daily, which earns slightly more, and daily compounding pushes the effective annual rate above the nominal one.
Does compounding frequency matter?
Yes. For the same nominal rate, more frequent compounding earns more: annual, quarterly and monthly step up the effective rate. This tool compounds annually, so it is a conservative estimate.
Can it handle regular contributions?
No. It models a single lump sum, without monthly deposits, withdrawals or reinvested dividends. Use a cash-flow calculator for those.