Investment calculator with monthly contributions
Enter the starting amount, how much you will save per month, the rate and the term to see the final balance and the year-by-year growth.
Free · no sign-up The values you type stay in your browser: nothing is sent or stored.
Final balance
R$102,710.47
- Total invested
- R$61,000.00
- Total interest
- R$41,710.47
Your result in words
Saving R$500.00 per month, starting from R$1,000.00, at 0.8% per month, in 10 years you reach R$102,710.47: R$61,000.00 invested and R$41,710.47 in interest.
Growth chart
| Total with interest | Invested | |
|---|---|---|
| 1 | R$7,371.51 | R$7,000.00 |
| 2 | R$14,382.32 | R$13,000.00 |
| 3 | R$22,096.59 | R$19,000.00 |
| 4 | R$30,584.91 | R$25,000.00 |
| 5 | R$39,924.92 | R$31,000.00 |
| 6 | R$50,202.11 | R$37,000.00 |
| 7 | R$61,510.49 | R$43,000.00 |
| 8 | R$73,953.54 | R$49,000.00 |
| 9 | R$87,645.11 | R$55,000.00 |
| 10 | R$102,710.47 | R$61,000.00 |
Detailed breakdown
| Year | Invested | Interest | Balance |
|---|---|---|---|
| 1 | R$7,000.00 | R$371.51 | R$7,371.51 |
| 2 | R$13,000.00 | R$1,382.32 | R$14,382.32 |
| 3 | R$19,000.00 | R$3,096.59 | R$22,096.59 |
| 4 | R$25,000.00 | R$5,584.91 | R$30,584.91 |
| 5 | R$31,000.00 | R$8,924.92 | R$39,924.92 |
| 6 | R$37,000.00 | R$13,202.11 | R$50,202.11 |
| 7 | R$43,000.00 | R$18,510.49 | R$61,510.49 |
| 8 | R$49,000.00 | R$24,953.54 | R$73,953.54 |
| 9 | R$55,000.00 | R$32,645.11 | R$87,645.11 |
| 10 | R$61,000.00 | R$41,710.47 | R$102,710.47 |
Informational estimate, without fees or inflation. Check taxes and charges for your case; the real result may differ.
How it works
How monthly contributions work
When you save an amount every month, each contribution starts earning interest from then on. Over time, most of the balance comes from interest and not from what you deposited: that is the effect of compound interest with consistency.
A tip
Consistency beats picking the best investment: a contribution that fits your budget and is never interrupted usually beats large, irregular ones.
Formula
How the math works
S with subscript k is the balance at the end of month k, i the monthly rate and A the monthly contribution. Each month the balance earns that month rate and the contribution is added at the end. The annual rate is converted to the equivalent monthly rate, and the initial amount earns from the first month.
Example
With round numbers, so you can check the math:
Saving R$500.00 per month, starting from R$1,000.00, at 0.8% per month, in 10 years you reach R$102,710.47: R$61,000.00 invested and R$41,710.47 in interest.
Frequently asked questions
Is the contribution made at the start or the end of the month?
At the end of the month: the first contribution only starts earning in the following month. Contributing at the start of the month earns a little more.
Is the rate fixed for the whole term?
Yes, the simulation uses a constant rate. In real life returns vary, so treat the result as an estimate.
Does it include income tax and inflation?
No. The balance is gross and in nominal values. After tax and inflation, the real gain is smaller.
Math checked by the JuntaTudo team · updated on Nov 12, 2026
