CDI Calculator: How to Calculate Returns in 2025
Learn how to calculate CDI returns, use a CDI calculator, and maximize your fixed income investments. Complete 2025 guide with examples.
The CDI (Certificado de Depósito Interbancário - Interbank Deposit Certificate) is one of the main indicators of the Brazilian financial market and serves as a benchmark for various fixed-income investments. In 2025, with an ever-changing economic scenario, understanding how to calculate CDI returns has become essential for those looking to grow their money safely and efficiently. In this article, you’ll learn everything about CDI, how to use a CDI calculator to simulate your investments and maximize your gains.
What is CDI
The Interbank Deposit Certificate is a fixed-income security that banks use to lend money to each other. When a financial institution needs funds to close the day within Central Bank requirements, it can borrow from another bank that has excess cash.
These operations generate a daily average rate, known as the CDI Rate, which is calculated by CETIP (now B3). This rate serves as a benchmark for various fixed-income investments in the Brazilian market, influencing everything from CDBs to DI funds.
How CDI works
CDI operations are relatively simple: daily, banks carry out lending operations among themselves with a one-business-day term. These operations are recorded at B3, which calculates the weighted average rate of these transactions.
The CDI rate value is published every business day by B3, serving as a reference for the financial market. For example, when you invest in a CDB that yields “100% of CDI,” it means your investment will yield exactly the CDI rate for that period.
CDI vs Selic Rate
Although often confused, CDI and Selic Rate have important differences:
The Selic Rate is set by the Central Bank’s Monetary Policy Committee (COPOM) every 45 days, being the basic interest rate of the Brazilian economy. The CDI rate, however, is formed by the market daily, in negotiations between banks.
In practice, the CDI rate always stays very close to Selic, usually a few percentage points below. For example, if Selic is at 12.25% per year, CDI typically stays around 12.15% per year.
CDI Rate in 2025
Projections for the year
Projections for the CDI rate in 2025 depend directly on the Selic Rate trajectory. With the Brazilian economic scenario facing inflationary pressures and fiscal challenges, market expectations indicate that Selic may remain at high levels during much of 2025.
Financial market analysts project that the CDI rate may vary between 11.5% and 13.5% per year in 2025, depending on COPOM decisions and the macroeconomic scenario. This range represents an interesting opportunity for fixed-income investors.
Influencing factors
Several factors influence the CDI rate in 2025:
Monetary Policy: COPOM decisions about the Selic Rate directly impact CDI. Increases in Selic lead to proportional increases in CDI.
Fiscal Scenario: Market perception about public account balance affects expectations of future interest rates.
Inflation: IPCA and its expectations influence monetary policy decisions, indirectly impacting CDI.
International Scenario: Monetary policies of developed countries, especially the United States, also influence domestic rates.
How to calculate CDI returns
Calculation formula
CDI return calculation follows a specific formula that considers daily compound capitalization. The basic formula is:
Final Value = Initial Value × (1 + Daily CDI Rate)^number of days
To convert the annual CDI rate to daily, use: Daily CDI Rate = (1 + Annual CDI Rate)^(1/252) - 1
The number 252 represents the business days in a year in the Brazilian financial market.
Practical example
Let’s calculate the return on a R$ 10,000.00 investment in a CDB that yields 100% of CDI, considering a CDI rate of 12% per year for 12 months:
- Daily CDI rate: (1 + 0.12)^(1/252) - 1 = 0.000453 or 0.0453% per day
- Formula application: R$ 10,000 × (1.000453)^252 = R$ 11,274.97
- Gross return: R$ 1,274.97
This calculation doesn’t consider taxes, which we’ll cover later. To simplify this process, you can use our CDI calculator that performs all calculations automatically, including taxation.
Investments that yield CDI
CDBs
Bank Deposit Certificates are the most common investments tied to CDI. Large banks usually offer CDBs that yield between 90% and 100% of CDI, while smaller banks may offer percentages above 100% of CDI, such as 110% or 120%.
For example, a CDB from a digital bank offering 115% of CDI means that if CDI is at 12% per year, your investment will yield 13.8% per year (12% × 1.15).
DI Funds
DI (Interbank Deposits) Funds are investment funds that invest at least 80% of their assets in CDI-related securities. These funds usually yield close to CDI, minus management fees.
The advantage of DI Funds is daily liquidity and professional management, but it’s important to check the fees charged, which can vary from 0.5% to 2% per year.
Selic Treasury
Selic Treasury is a government bond that follows the Selic Rate variation, maintaining very close correlation with CDI. It’s considered the safest investment in the country, with daily liquidity and low cost.
Although it doesn’t yield exactly CDI, Selic Treasury offers very similar profitability, being an excellent option for emergency reserves.
Taxation on CDI
Investments tied to CDI follow the regressive Income Tax table:
- Up to 180 days: 22.5%
- From 181 to 360 days: 20%
- From 361 to 720 days: 17.5%
- Over 720 days: 15%
Besides income tax, there’s IOF (Tax on Financial Operations) for redemptions in the first 30 days, following a daily regressive table from 96% on the first day to 0% on the 30th day.
Returning to our previous example of R$ 10,000.00 invested for 12 months with a return of R$ 1,274.97:
- Income tax (20% for 360-day period): R$ 254.99
- Net return: R$ 1,019.98
- Final net value: R$ 11,019.98
Investment simulation
To demonstrate the importance of simulating CDI investments, let’s compare different scenarios:
Scenario 1: R$ 50,000.00 invested in 100% CDI CDB (12% per year) for 24 months
- Gross return: R$ 12,974.00
- Income tax (17.5%): R$ 2,270.45
- Net return: R$ 10,703.55
Scenario 2: R$ 50,000.00 invested in 115% CDI CDB (13.8% per year) for 24 months
- Gross return: R$ 15,521.10
- Income tax (17.5%): R$ 2,716.19
- Net return: R$ 12,804.91
The 15% difference in compensation resulted in R$ 2,101.36 more in net return, showing the importance of seeking the best opportunities in the market.
Frequently Asked Questions
What does it mean when an investment yields 120% of CDI?
It means the investment pays 1.2 times the CDI rate. If CDI is at 12% per year, this investment will yield 14.4% per year (12% × 1.2). It’s common for smaller banks to offer percentages above 100% of CDI to attract investors.
What’s the difference between CDI and Selic for investors?
For individual investors, the practical difference is small. CDI always stays very close to Selic, usually a few tenths below. CDI-linked investments include CDBs and DI Funds, while Selic Treasury directly follows the Selic rate.
How is CDI calculated daily?
CDI is calculated by B3 as the weighted average of interbank lending operations carried out during the day. This rate is published daily after market close and serves as a reference for investment compensation the next day.
Is it better to invest in CDB or Selic Treasury in 2025?
It depends on your profile and objectives. Selic Treasury offers maximum security and daily liquidity, ideal for emergency reserves. CDBs may offer superior returns (especially above 100% of CDI), but have credit risk from the financial institution and may have waiting periods.
When should I use a CDI calculator?
Use a CDI calculator whenever you want to simulate fixed-income investments tied to this rate. It’s especially useful for comparing different terms, amounts, and CDI percentages, plus calculating correct taxation on returns.
Can CDI be negative?
In theory, yes, but in practice it’s extremely rare in Brazil. This would only happen in severe crisis scenarios or very specific monetary policies. Historically, CDI has always been positive in the Brazilian market.
How to choose the best CDI-linked investment?
Compare the CDI percentage offered, waiting period, financial institution’s stability, and your liquidity needs. Use simulators to calculate net return considering taxation. Diversify among different institutions to reduce risks.