Compound Interest Calculator
See how a beginning balance, regular contributions, time, and an assumed return work together in an illustrative projection.
Explore a projection
Enter figures, then select show projection.
How to use it
- Choose a starting balance and a monthly amount you could contribute consistently.
- Enter a time horizon and an assumption you understand is not guaranteed.
- Compare several scenarios; a projection is a way to learn, not a promise of a result.
Assumptions and limitations
The tool uses the existing monthly compounding formula and assumes the contribution and rate stay unchanged. It does not account for losses, taxes, inflation, account fees, contribution limits, withdrawals, or timing differences. Investments can lose value.
Question readers ask
Is the assumed return a forecast?
No. It is an input you select for an illustration. Markets do not deliver a constant return, and past results do not guarantee future results.
Educational disclaimer: General education only; not investment, tax, or personalized financial advice.