How to use Compound Interest Calculator
- Enter the starting amount and the annual interest rate.
- Set the number of years and the compounding period.
- Add a regular contribution and choose start or end of period.
- The final balance and yearly table update as you change the fields.
Example: Compound Interest Calculator
Grow 1,000 at 5 percent compounded every month for 10 years with no further deposits.
Options
- Compounding
- Once a year, twice a year, quarterly, monthly, weekly, daily or continuously. More frequent compounding gives slightly more for the same stated rate.
- Regular contribution
- A fixed amount added once per compounding period, or 0 for a single deposit. Continuous compounding refuses contributions.
- Contribution timing
- A contribution at the start of a period also earns that period's interest, so it ends up worth more.
Supported inputs and limits
Where your input is processed
This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.
Why more frequent compounding pays slightly more
Splitting the annual rate into more periods applies interest to interest a little sooner. The effect is bounded: as the number of periods grows, the yearly growth factor approaches e raised to the annual rate, which is what continuous compounding uses. That is why 1,000 at 5% for a year reaches 1,050.00 compounded once a year and only 1,051.27 continuously. The yearly return including compounding is what some accounts call the annual percentage yield.
Investor.gov compound interest calculator, U.S. Securities and Exchange Commission
Questions about Compound Interest Calculator
How much does compounding frequency matter?
Little at small amounts. 1,000 at 5% for a year is 1,050.00 compounded yearly, 1,051.16 monthly and 1,051.27 continuously. The gap widens over a longer term.
Why can't I add contributions with continuous compounding?
There are no discrete periods, so there is no point at which a deposit lands. Choose a period such as monthly instead.
Why was my term rejected when I added a contribution?
Contributions are added once per full compounding period. A fractional period count is refused rather than rounded, so use whole periods or set the contribution to 0.
Do regular contributions change the total much?
Yes. Starting at 1,000 and adding 200 a month at 6% compounded monthly for ten years reaches 34,595.27. Your own money is the 1,000 start plus 24,000 in deposits, so 9,595.27 is interest.