Compound Interest Calculator
Calculate compound interest and investment growth with regular contributions. See future value, total contributions, interest, and a yearly breakdown.
| Year | Balance | Interest to date |
|---|---|---|
| 1 | 13,201.42 | 801.42 |
| 2 | 16,634.27 | 1,834.27 |
| 3 | 20,315.28 | 3,115.28 |
| 4 | 24,262.39 | 4,662.39 |
| 5 | 28,494.83 | 6,494.83 |
| 6 | 33,033.24 | 8,633.24 |
| 7 | 37,899.74 | 11,099.74 |
| 8 | 43,118.03 | 13,918.03 |
| 9 | 48,713.55 | 17,113.55 |
| 10 | 54,713.58 | 20,713.58 |
| 11 | 61,147.34 | 24,747.34 |
| 12 | 68,046.20 | 29,246.20 |
| 13 | 75,443.79 | 34,243.79 |
| 14 | 83,376.14 | 39,776.14 |
| 15 | 91,881.93 | 45,881.93 |
| 16 | 101,002.60 | 52,602.60 |
| 17 | 110,782.60 | 59,982.60 |
| 18 | 121,269.60 | 68,069.60 |
| 19 | 132,514.70 | 76,914.70 |
| 20 | 144,572.72 | 86,572.72 |
See how your money grows with compound interest. Enter a starting amount, an interest rate, a time horizon, and optional regular contributions, and the calculator projects your future value along with how much is your own money versus interest earned — plus a year-by-year breakdown.
How to use it
No account, no upload — it all happens on your device.
The compound interest formula
How the future value is built.
For a lump sum, the future value is A = P(1 + r/n)^(n·t), where P is the principal, r the annual rate, n the number of compounds per year, and t the years. Regular contributions are added each period and compound from the moment they land.
| Symbol | Meaning |
|---|---|
| P | Principal — your starting amount |
| r | Annual interest rate (as a decimal) |
| n | Compounding periods per year |
| t | Number of years |
Why time matters more than rate
- Start early. Because growth compounds, an extra decade in the market often beats a higher rate over a shorter period.
- Contribute consistently. Regular monthly contributions can dwarf the starting balance over long horizons — try setting the starting amount low and the contribution high to see it.
- Estimates, not guarantees.Real returns vary year to year and aren't a flat rate. Use this as a planning tool, not a promise.