Compound Interest Calculator
Project the long-term growth of an investment. Combine a starting balance, an expected annual return, and optional monthly contributions to see the power of compounding.
Final value after 10 years
$23,191.54
1.78× your contributions
- Total contributed
- $13,000.00
- Total growth
- $10,191.54
Year-by-year balance
| Year | Balance |
|---|---|
| 1 | $2,361.27 |
| 2 | $3,865.08 |
| 3 | $5,526.36 |
| 4 | $7,361.60 |
| 5 | $9,389.02 |
| 6 | $11,628.73 |
| 7 | $14,102.96 |
| 8 | $16,836.28 |
| 9 | $19,855.82 |
| 10 | $23,191.54 |
How it works
Each month your balance earns one-twelfth of the annual return, then your monthly contribution is added. Because returns are calculated on the growing balance — not just your original deposit — gains compound on top of previous gains. Over many years this snowball effect can dwarf the amount you actually contributed.
Total contributed adds your initial amount to every monthly deposit. Total growth is the final value minus everything you put in, and the multiple shows how many times your contributions the balance has become.
FAQ
How often does interest compound?
Monthly. The annual return is divided by twelve and applied each month, with contributions added at the end of every month.
Is the expected return guaranteed?
No. The return is an assumption you choose. Actual investment returns vary year to year and can be negative, especially with crypto.
Does it account for inflation or fees?
No. Figures are nominal and exclude fees, taxes, and inflation. To model real purchasing power, enter an inflation-adjusted return.
Not financial advice.