Fixed income simulator: CDB, LCI, LCA and Treasury
Compare two investments side by side, with the regressive income tax already deducted.
Central Bank CDI on 15/10/2026: 13.65% per year. You can edit it.
- Option A · net
- R$11,126.13
- Option B · net
- R$11,220.54
- You invested
- R$10,000.00
Use the legend buttons to show or hide a series.
Option B earns R$94.41 more after tax.
| Option A | Option B | |
|---|---|---|
| Total invested | R$10,000.00 | R$10,000.00 |
| Gross amount | R$11,365.00 | R$11,220.54 |
| Income tax | R$238.88 | R$0.00 |
| Net amount | R$11,126.13 | R$11,220.54 |
| Net return | R$1,126.13 | R$1,220.54 |
| Net return over the period | 11.26% | 12.21% |
- Simulation with a constant CDI over the whole term. The real CDI will vary.
- Regressive income tax per contribution: 22.5% up to 180 days, 20% from 181 to 360, 17.5% from 361 to 720 and 15% above 720 days.
- Does not include IOF (only applies in the first 30 days), B3 custody fees on Tesouro Direto, or mark-to-market before maturity.
- Monthly contribution made at the start of each month, including the first. Counts 21 business days per month.
CDI source: Central Bank of Brazil (SGS, series 4389).
How the calculation works
How to compare fixed income after tax
Enter an initial amount, monthly contribution and term. Set each option to a percentage of CDI or a fixed annual rate, and choose its taxation. The chart compares net balances with total contributions. You can also add gross balances to see the effect of income tax.
A worked example
In a hypothetical scenario of R$10,000.00 at 12% a year for 12 months, with no further deposits and regressive income tax, the simulator returns R$11,200.00 gross, R$210.00 in tax and R$10,990.00 net. The rate is illustrative.
Common questions
Does today’s CDI guarantee future returns?
No. The simulation keeps the entered CDI constant for the whole term. The rate can change, affecting floating-rate investments. You can edit it to test other assumptions.
How are monthly contributions calculated?
They enter at the start of each month, including the first. Each contribution has its own holding period for regressive income tax. The model uses 21 business days per month and 365/12 calendar days to estimate tax bands.
Does the highest net balance mean the best investment?
The chart only compares the assumptions you enter. It does not assess credit risk, liquidity or guarantees. It also excludes IOF, B3 custody fees and price fluctuations before maturity.
Sources and methodology
Methodology and maintenance: Today Brazil. Guide updated on .
Continue your simulation
Informational simulation built on public data. It is not investment advice, nor financial, legal or tax advice.