Compound interest calculator
See how your money grows with an initial amount, monthly contributions and compound interest, using today’s Selic and CDI rates. Free, no sign-up.
Compound interest calculator
Final balance
R$125,302.74
- Total invested
- R$61,000.00
- R$1,000.00 upfront + 120 contributions of R$500.00
- Total interest
- R$64,302.74
- 51.32% of final balance
Equivalent monthly rate: 1.08%
Anyone who opens the link sees this same simulation. Nothing is stored.
Show year-by-year table
| Year | Total invested | Total interest | Final balance |
|---|---|---|---|
| 1 | 7,000 | 507 | 7,507 |
| 2 | 13,000 | 1,908 | 14,908 |
| 3 | 19,000 | 4,328 | 23,328 |
| 4 | 25,000 | 7,904 | 32,904 |
| 5 | 31,000 | 12,798 | 43,798 |
| 6 | 37,000 | 19,190 | 56,190 |
| 7 | 43,000 | 27,285 | 70,285 |
| 8 | 49,000 | 37,319 | 86,319 |
| 9 | 55,000 | 49,557 | 104,557 |
| 10 | 61,000 | 64,303 | 125,303 |
Contributions at the end of each month (the first one at the end of month 1). Yearly rate converted to the equivalent monthly rate. Taxes, fees and inflation are not considered: to compare investments after tax, use the fixed income calculator.
How to use the calculator
- Enter the initial amount you already have saved.
- Set how much you plan to contribute every month.
- Choose the interest rate — yearly or monthly. Shortcuts fill in today's Selic and CDI rates from Brazil's Central Bank.
- Adjust the time period in years or months.
The result shows the final balance, how much came out of your pocket and how much came from interest, with year-by-year growth.
The formula
With monthly compounding and contributions at the end of each month:
FV = P·(1+i)ⁿ + A·[(1+i)ⁿ − 1] / i
Where P is the initial amount, A the monthly contribution, i the monthly rate and n the number of months. A yearly rate is converted using the equivalent rate: i = (1 + yearly rate)^(1/12) − 1.
Limitations
The simulation does not account for income tax, fees or inflation. Use it as a reference, not as a promise of returns.