Compound Interest Calculator
See how your money grows over time with compound interest and regular contributions.
Year-by-Year Growth
| Year | Year-End Balance | Interest This Year | Total Contributed |
|---|
For educational purposes only — not financial advice.
How to use
- Enter your starting principal — the initial amount you're investing.
- Set the annual interest rate (e.g., 7% for a stock market index fund average).
- Choose how often interest compounds — daily and monthly are most common.
- Set the number of years you plan to invest.
- Add a monthly contribution to see the power of regular investing.
- The Rule of 72 shows roughly how many years it takes to double your money.
About this Compound Interest
Compounding frequency (daily vs. annually) at the same nominal rate meaningfully changes effective return over time — which is why frequency matters as much as the stated rate. This tool lets you set compounding frequency to see the actual effect on growth.