CDI Today: What it is, How It Works and How to Calculate Income in 2026
If you have ever invested in a CDB, LCI, LCA, DI fund or automatic income account, you have certainly seen the expression "100% of the CDI", "110% of the CDI" or "90% of the CDI". But what exactly is the CDI? How is it determined? And how to calculate how much you will actually get back?
The CDI is the most used reference in the Brazilian fixed income market — and understanding it is essential for making good investment decisions. Use our Savings Calculator vs CDI to compare income in seconds.
What is the CDI?
CDI (Certificate of Interbank Deposit) is a private security issued by banks to raise funds from other banks to cover their daily cash position. Just as banks lend money to people, they also lend to each other — and the CDI is the legal instrument for these operations.
The CDI rate is determined by the weighted average of the rates practiced in these daily interbank operations, calculated and published by B3 (formerly CETIP). By law, the Central Bank requires banks to end each day with positive cash — therefore, banks with excess cash lend to those with a deficit, and the resulting rate is the CDI.
CDI vs Selic: What’s the Difference?
| Feature | CDI | Selic |
|---|---|---|
| What is | Private interbank rate | Basic interest rate for the economy |
| Who determines | Market (supply and demand) | Copom (Central Bank) |
| Base | Operations between private banks | Operations with federal public securities |
| Term of operations | 1 day (overnight) | 1 business day (overnight) |
| Disclosure | B3, daily | Central Bank, daily |
In practice: The CDI and Selic are virtually identical — the daily CDI rate is less than 0.01 percentage point of the Selic Over. When they say "100% of the CDI", they are saying almost the same as "100% of the Selic".
Current CDI Rate in 2026
Annual CDI rate 2026: The current CDI rate follows the Selic rate defined by Copom. Consult Banco Central do Brasil for the exact and updated value of the daily Selic Over rate.
As a historical reference:
| Period | Selic / CDI rate |
|---|---|
| 2021 (start) | 2.00% per year |
| 2022 (peak) | 13.75% per year |
| 2023 | 11.75% per year |
| 2024 | 12.25% per year |
| 2025 | ~13.75% per year |
| 2026 | See BCB |
How to Calculate the 100% CDI Yield
To calculate the return on an investment linked to the CDI, use the compound interest formula with the daily rate:
Amount = Main × (1 + CDI_daily)^business_days
The daily CDI rate is calculated from the annual rate:
daily_CDI = (1 + annual_CDI)^(1/252) − 1
Using 252 business days (Brazilian financial market standard).
Practical Example: $10,000 at 100% of the CDI for 1 year
Assuming annual CDI of 13% per year:
CDI_diário = (1,13)^(1/252) − 1 = 0,04855% ao dia útil
Montante = 10.000 × (1,0004855)^252
Montante = 10.000 × 1,13 = R$ 11.300,00
Gross income: $ 1,300.00
But you need to deduct Income Tax (CDB is taxed):
- Term of 365 days → rate of 17.5%
- IR = $ 1.300 × 17,5% = $ 227.50
- Net income: $ 1,072.50 (10.7% per year net)
Comparison: 100% of CDI vs Savings
Savings have a different yield depending on the Selic:
- Selic ≤ 8.5% per year: Savings yields 70% of Selic + TR
- Selic > 8.5% per year: Savings yields 0.5% per month + TR (= 6.17% per year + TR)
Savings are exempt from income tax for individuals.
Comparison with CDI at 13% per year:
| Investment | Gross Income | GO | Net Income |
|---|---|---|---|
| Savings | ~6.17% + TR | Exempt | ~6.17% per year |
| CBD 100% CDI (365 days) | 13.0% | 17.5% | ~10.7% per year |
| CDB 80% CDI (365 days) | 10.4% | 17.5% | ~8.6% per year |
| CDB 110% CDI (365 days) | 14.3% | 17.5% | ~11.8% per year |
| LCI/LCA 90% CDI | ~11.7% | Exempt | ~11.7% per year |
| LCI/LCA 95% CDI | ~12.35% | Exempt | ~12.35% per year |
Insight: IR-exempt LCI and LCA with 90% of the CDI can yield more liquid than a CDB with 100% of the taxed CDI. Always compare by net income!
Monthly Income Table: CDI of 13% per year
| Month | Accumulated Income | Amount ($ 10.000) |
|---|---|---|
| 1 | 1,024% | $ 10,102.40 |
| 3 | 3.091% | $ 10.309,10 |
| 6 | 6,278% | $ 10,627.80 |
| 12 | 13.0% | $ 11.300,00 |
| 24 | 27,69% | $ 12,769.00 |
| 36 | 44.29% | $ 14.429,00 |
| 60 | 84,24% | $ 18,424.00 |
When the CDI Varies: Impact on Investments
The CDI follows the Selic, which is adjusted by Copom in meetings every 45 days. When Selic rises:
- Post-fixed investments (CDB, LCI, LCA, DI funds) automatically yield more
- Prefixed securities (prefixed CDB, prefixed Treasury) are relatively less attractive in the secondary market
When Selic falls:
- Post-fixes yield less
- Prefixed and IPCA+ become more attractive to lock in the current rate
How to Compare Fixed Income Investments
The correct way to compare:
- Always calculate by net income (post-IR)
- Consider liquidity: CDB with daily liquidity may have a lower rate; without liquidity may have a higher rate
- Analyze the due date: Regressive income tax rates (22.5% → 15%)
- Evaluate the risk: CDB and LCI up to $250,000 are guaranteed by the FGC (Credit Guarantee Fund)
Comparison Formula (Base 100% equivalent CDI)
To compare an exempt LCI/LCA with a taxed CDB:
CDI LCI equivalent = % CDI × 1 / (1 − IR_rate)
Example: LCI at 90% of the CDI for 12 months (IR rate that would be 17.5%): Equivalent CDI = 90% / (1 − 0.175) = 90% / 0.825 = 109.1% of gross CDI
In other words, an LCI of 90% of the CDI is equivalent to a CDB of 109.1% of the CDI for the same period.
Common Mistakes When Investing in the CDI
Compare gross rates without adjusting for IR: The CDB of 110% of the CDI is not necessarily better than the LCI of 90% of the CDI — it depends on the term and the rate.
Not observing the grace period: Many CDBs with high rates have a grace period of 1 to 3 years. If you need to redeem earlier, you lose the fee.
Ignore the FGC: Applications above $250,000 per CPF per institution are not covered by the FGC. Diversify between banks.
Invest all money in daily liquidity: Daily liquidity CDB has lower rates. For emergency reserves, use daily liquidity; for long-term goals, braking longer increases the rate.
Do not renew upon maturity: Leaving the money in a current account after the CDB expires yields zero. Set up automatic reinvestment or monitor maturities.
Frequently Asked Questions (FAQ)
1. What does investment at 100% of the CDI mean?
It means that the gross return on the investment is identical to the CDI rate for the period. If the CDI was 13% in the year, the investment yielded 13% gross. In practice, Income Tax is still levied on profits (except LCI/LCA and savings, which are exempt).
2. What is the difference between CDI and CBD?
The CDI is a reference rate — the index. The CDB (Bank Deposit Certificate) is an investment product issued by banks. When the bank offers a CDB at 100% of the CDI, it means that the profitability of the CDB will follow the CDI rate during the application period.
3. Does the CDI change frequently?
Yes. The daily CDI rate fluctuates with the interbank market, but follows the Selic Over very closely. When the Copom (Monetary Policy Committee) raises or reduces the Selic, the CDI follows immediately. The daily variations in the CDI are minimal — the significant change only occurs on the dates of the Copom meetings.
4. Do I invest in CDB 100% CDI or Treasury Selic?
Both have yields close to the CDI/Selic. The Selic Treasury is considered the safest investment in Brazil (sovereign risk). The CDB depends on the solidity of the issuing bank, but has FGC up to $250,000. For investments above this value, the Treasury Selic may be preferable due to the absence of credit risk.
5. How do I know today's CDI rate?
The CDI rate is published daily by B3 (https://www.b3.com.br) and the Central Bank (https://www.bcb.gov.br). Investment platforms such as Tesouro Direto, Rico, XP and NuInvest also display the rate in real time.
6. Does the savings yield more than 100% of the CDI?
No, in the vast majority of scenarios. With Selic above 8.5% per year, savings yield only 6.17% per year + TR — well below 100% of the CDI (which follows the Selic). Savings may only be slightly competitive compared to very short-term taxed CDBs, but it never surpasses exempt quality investments such as LCI and LCA.
Compare Investments Now
Use our Savings vs CDI Calculator to compare savings with any percentage of the CDI. See also:
Related calculators:
- CDB, LCI and LCA calculator — compare fixed income with IR
- Treasury Direct Simulator — compare with public bonds
- Compound Interest Calculator — understand exponential growth
- Fixed Income Calculator — general fixed income simulator