Are you thinking about investing—or do you already invest—but still have questions about which fixed income Is it really worth it? CDB, LCI, Tesouro Direto, savings accounts… each has different rules regarding returns, taxes, and terms, and comparing all of that off the top of your head is complicated.
That's why we created this free calculator: in less than a minute, you can simulate any fixed-income investment, see the exact net amount you'll receive, find out how much income tax you'll pay, and automatically compare all the options side by side.
What is fixed income?
Fixed income is an investment category in which the The rule for calculating income is defined at the time of application.. That doesn't mean the final amount is the same for everyone—it varies depending on the amount invested, the term, and the benchmark index (such as the CDI or IPCA). But you know, right from the start, how your money will grow.
Think of it this way: when you invest in a CDB, you’re lending money to a bank. When you invest in Tesouro Direto, you’re lending to the federal government. In both cases, they return the principal plus interest calculated at a rate agreed upon at the outset.
It's quite different from the variable income (such as stocks), where returns depend on the company's performance and market sentiment. For this reason, fixed-income investments are recommended for those who want to security, predictability, and stability — especially for beginners.
What are the main types of fixed-income securities?
The calculator above simulates the four main fixed-income products available in Brazil. Here's how each one works:
CDB — Bank Certificate of Deposit
CDBs are issued by banks and are one of the most popular investment options in the country. When you invest in one, you lend money to the bank in exchange for a rate of return.
The yield can be floating-rate (% based on the CDI), fixed-rate (fixed annual rate), or hybrid (IPCA + fixed rate). It is calculated Income tax with a regressive interest rate of 22.5% for redemptions within 6 months, rising to 15% for terms longer than 2 years. During the first 30 days, the IOF tax also applies, which is progressively reduced until it reaches zero. The CDB is guaranteed by the FGC up to R$ 250,000 by CPF per bank.
💡 Look for CDBs that yield more than 100% from CDI. Many digital banks offer 110%, 120%, or more, especially for longer terms.
LCI and LCA — Letters of Credit
The LCI (Real Estate Credit Note) and the LCA (Agribusiness Credit Note) are very similar to the CDB, with one key difference: are completely exempt from individual income tax.
The yield is usually linked to the CDI (90%, 92%, 95%) or is fixed. These are exempt from income tax for individuals and covered by the FGC up to R$ 250,000 per bank. Generally speaking, liquidity does not allow for early redemption—always check the lock-in period before investing.
💡 An LCI at 92% of the CDI could be more advantageous that a CDB yields 105% based on the CDI after you deduct income tax. Use the calculator above and compare!
Treasury Direct
Tesouro Direto is the federal government’s program for selling government securities to individual investors online. It is considered the safest investment in Brazil, as it is backed by the government itself.
The main titles available are:
O Selic Treasury It tracks the benchmark interest rate and is ideal for an emergency fund, as it offers daily liquidity and low volatility. The Prefixed Treasury guarantees a fixed rate set at the time of purchase—you know exactly how much you'll receive when it matures. On the other hand, the IPCA+ Treasury It adds a fixed rate to inflation, protecting your purchasing power in the long term.
All Tesouro Direto securities have a regressive income tax rate (the same schedule as the CDB) and a B3 custody fee of 0.201 TP3T per year — already included in the calculator's simulation — and allow you to invest starting at R$ 30,00.
Savings
Savings accounts are the most traditional form of investment in Brazil. They’re simple, involve no red tape, and are tax-free—but they also offer the lowest returns among the available options.
With the Selic rate above 8.5% per year, it yields 0.5% per month + TR, equivalent to approximately 6.17% per year. It is exempt from income tax for individuals, covered by the FGC, and offers daily liquidity—but interest is paid only on the investment’s anniversary date; in other words, you lose that month’s interest if you redeem it early.
⚠️ Even with the income tax exemption, savings accounts almost always lose out to other options. Run a simulation on the calculator and see the difference in the “Comparison” field.
How to Use the Fixed Income Calculator, Step by Step
The calculator is right at the top of this page. Here's how to fill out each field correctly:
Step 1 — Enter the starting amount
Enter the amount you plan to invest now. It can be any amount—Tesouro Direto accepts investments starting at R$ 30, and many CDBs from digital banks accept investments starting at R$ 1.
Step 2 — Set your monthly contribution
If you plan to deposit a fixed amount each month in addition to the initial deposit, enter it here. Otherwise, leave it at zero. Regular contributions make a big difference in the long run thanks to the power of compound interest.
Step 3 — Choose the deadline
Use the slider or enter the number of months (or years) you plan to hold the investment. The term directly affects the income tax rate: for terms longer than 2 years, the rate drops to 15%—the lowest possible rate for CDBs and Treasury bonds.
Step 4 — Select the investment
Click on the tab for the product you want to simulate: CDB, LCI/LCA, Tesouro Direto, or Savings Account. Each tab displays the fields specific to that investment.
Step 5 — Set the rate
For CDBs: Enter the percentage of the CDI offered by the bank (e.g., 110) or the fixed rate. For Treasury securities: Select the type of security and enter the spread. The calculator automatically uses the current CDI, Selic, and IPCA rates.
Step 6 — Click “Simulate Now”
The results are shown below, along with:
The results show the gross and net amounts at the end of the period, the total return before and after income tax, how much you will pay in income tax and the financial transactions tax (IOF), the net effective annual rate, a graph showing month-by-month changes, a detailed table of annual changes, and an automatic comparison of all investments.
What is the CDI, and why is it the benchmark for fixed-income securities?
CDI stands for Interbank Certificate of Deposit. It is the rate that banks use to lend money to each other for very short terms. In practice, it closely tracks the Selic rate—the Brazilian economy’s benchmark interest rate.
When a CDB promises “CDI 110%”, which means you’ll earn 10% more than that benchmark. With a CDI of 10.5% per year, this amounts to a gross return of 11.55% per year—well above what you’d earn in a savings account.
The CDI is reviewed periodically by the Central Bank through meetings of the Copom (Monetary Policy Committee). Therefore, the figures shown in the calculator are estimates based on the current rate.
How does the regressive income tax work for fixed-income investments?
Income tax on CDBs and Tesouro Direto follows a regressive tax schedule—the longer you hold the investment, the less tax you pay:
| Application Deadline | Income tax rate | Impact |
|---|---|---|
| Up to 180 days (6 months) | 22,5% | Too high — avoid redeeming before then |
| From 181 to 360 days (up to 1 year) | 20% | High — it's better to wait until the second year |
| From 361 to 720 days (up to 2 years) | 17,5% | Moderate |
| More than 720 days (more than 2 years) | 15% | More efficient — lower tax burden |
Income tax is levied on only about income, never on the amount you invested. In addition, during the first 30 days, there is also the IOF (Tax on Financial Transactions), which decreases daily until it reaches zero on the 30th day.
💡 Therefore, it’s best not to redeem the investment before 30 days (IOF) and to hold it for more than 2 years so you’ll only pay 15% in income tax on the gains.
Compound interest: Why does the term make such a difference?
Compound interest means you earn interest on the interest you’ve already accumulated. Over time, this effect creates exponential growth—commonly referred to as the “snowball effect.”.
Practical example using 10,000 R$ applied at 10% per year:
| Deadline | Simple interest | Compound interest | Difference |
|---|---|---|---|
| 5 years | R$ 15,000 | R$ 16,105 | + R$ 1,105 |
| 10 years | R$ 20,000 | R$ 25,937 | + R$ 5,937 |
| 20 years | R$ 30,000 | R$ 67,275 | + R$ 37,275 |
Do you see the difference? Over 20 years, compound interest generates more than double the amount compared to simple interest. That's why it's so important to start investing early—even with small amounts.
Which fixed-income investment should you choose?
There's no single answer—it depends on your goal and your timeline. Here's a quick guide:
To emergency reserve, the Selic Treasury or a CDB with daily liquidity are the best options—the money needs to be available at any time. For the purpose of short term (up to 1 year), opt for a digital bank's CDB or a Tesouro Selic bond, and avoid redeeming them before 180 days to avoid paying 22.51 TP3T in income tax. In the medium term (1 to 3 years), it's worth comparing CDBs and LCIs/LCAs using the calculator—the LCI usually comes out on top because of the income tax exemption. For the long term (more than 3 years), the IPCA+ Treasury bond is the smartest option for protecting your purchasing power against inflation. As for savings accounts, they’re generally not the best choice—run a simulation and see how much you’re missing out on.
Frequently Asked Questions About Fixed Income
What is fixed income?
Fixed income is an investment category in which the formula for calculating returns is set at the time of investment. You lend money to a bank (CDB, LCI, LCA) or to the government (Tesouro Direto) and receive the principal back, adjusted by an agreed-upon rate. It is recommended for those seeking security and predictability.
What is the difference between a CDB and an LCI?
Both CDBs and LCIs are issued by banks, but LCIs are exempt from individual income tax. Therefore, an LCI at 92% of the CDI may be more advantageous than a CDB at 105% of the CDI after income tax is deducted. Use the calculator above to compare the net amounts.
How much does R$ 10,000 yield in fixed income?
It depends on the product and the term. For a CDB at 110% above the CDI (with the CDI at 10.5% per annum), R$ 10,000 would yield approximately R$ 924 gross in 12 months, or about R$ 738 net after a 17.5% income tax rate. Use the calculator above to run a simulation with the exact amounts you plan to invest.
Is saving still worth it?
With the Selic rate above 8.5% per year, savings accounts yield only 0.5% per month + TR, which is equivalent to about 6.17% per year. Even though they are exempt from income tax, they yield less than CDBs that offer rates 80% above the CDI and the Treasury Selic. In general, there are more profitable options that offer the same level of security.
Do I have to pay income tax on fixed-income investments?
It depends on the product. CDBs and Tesouro Direto have a regressive income tax rate: 22.5% for up to 180 days, 20% for up to 360 days, 17.5% for up to 720 days, and 15% for more than 720 days. LCI, LCA, and savings accounts are exempt from income tax for individuals. The tax is always levied only on the income, never on the amount invested.
Is my money safe in fixed-income investments?
CDBs, LCIs, and LCAs are guaranteed by the FGC (Credit Guarantee Fund) up to R$ 250,000 per CPF per institution. Tesouro Direto is guaranteed by the federal government—the safest investment in Brazil. Savings accounts are also covered by the FGC up to the same limit.
What is the best fixed-income investment?
It depends on your goal: for an emergency fund, the Selic Treasury Bond is ideal because of its daily liquidity. For the medium term (1 to 3 years), compare CDBs and LCIs using the calculator—the LCI may come out on top due to its income tax exemption. For the long term (more than 3 years), the IPCA+ Treasury bond is excellent for protecting purchasing power against inflation.
What is the CDI?
The CDI (Interbank Deposit Certificate) is the rate banks use for very short-term loans to one another. It closely tracks the Selic rate and serves as the main benchmark for fixed income in Brazil. When a CDB offers “110% of the CDI,” it means it yields 10% above that benchmark rate.
Did you like the simulator? Bookmark this page so you can refer to it whenever you want to compare investments. Have any questions? Leave them in the comments—we'll answer them all!
