Compound Interest Calculator
Last updated: May 10, 2026See how savings grow over time.
Compound Interest Calculator is a free online calculator to see how savings grow over time. It runs entirely in your browser, so your files never leave your device — nothing is uploaded. There's no sign-up, no watermark, and it works on any modern browser on desktop or mobile.
Disclaimer: This calculator is for informational and educational purposes only and is not financial advice. Actual figures depend on your provider, interest rates, fees, taxes and personal circumstances. Consult a qualified financial professional before making financial decisions.
How to use Compound Interest Calculator
This compound interest calculator shows how a lump sum grows when interest earns interest, using A = P times (1 + r/n)^(n times t), where P is the principal, r the annual rate, n the compounding frequency and t the years. Adjust the principal, rate, time and frequency to watch your balance build year by year. Savers and investors use it to compare accounts and understand long-term growth.
Read the full guide: Compound Interest Formula: How to Calculate It + Examples
- 1Enter your starting principal, annual interest rate and number of years.
- 2Choose how often interest compounds, such as yearly, quarterly, monthly or daily.
- 3Read the final balance and total interest, with the year-by-year growth shown.
Frequency matters
Compare yearly versus monthly or daily compounding to see how often-ness boosts returns.
Year-by-year view
Track how the balance climbs each year instead of seeing only the final number.
Separates interest earned
It shows total interest apart from your original principal so growth is clear.
Compare two bank account offers
When two banks quote similar rates but compound differently, the higher number is not always the better deal. Enter the same principal and term for each, then switch the compounding frequency between monthly, quarterly, and annually. The future value reveals which account actually pays more, so you can pick the offer that grows your deposit fastest before signing up.
Project a one-time lump sum to a goal
Got a bonus, tax refund, or inheritance you plan to park and leave untouched? Enter that single amount as the principal, set your expected annual rate, and stretch the years out to your target date. The tool shows the future value and total interest earned, helping you see whether a one-off deposit alone reaches a down-payment or retirement milestone.
Check a quoted maturity or APY figure
Banks and ads often advertise a maturity amount or yield without showing the math. Plug in the same principal, rate, term, and compounding frequency they used, then compare the calculated future value against their quoted number. Any mismatch points to hidden fees, a different compounding basis, or a nominal-versus-effective rate gap worth questioning before you commit.
Compound Interest Calculator — frequently asked questions
What is the compound interest formula?
The future value is A = P(1 + r/n)^(nt). P is the principal, r is the annual rate as a decimal, n is how many times interest compounds per year, and t is the number of years. Interest earned is simply A minus P.
How does compounding frequency change the result?
More frequent compounding means interest is added to the balance sooner and starts earning its own interest, so the total grows slightly faster. Daily compounding yields a bit more than monthly, which yields more than annual, at the same rate.
Does this account for regular deposits?
This calculator models a single lump sum left to grow. If you plan to add money every month, a SIP or recurring deposit calculation is the better fit since it compounds each contribution separately.
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