CDT Calculator: Gross Interest, Withholding Tax, Net Return, and Final Balance
A CDT (Certificado de Depósito a Término — fixed-term certificate of deposit) is Colombia’s most widely used bank savings instrument for capital preservation with predictable returns. You commit a fixed amount for a defined period, and the bank pays a fixed nominal interest rate. At maturity you receive principal plus net interest, after the bank automatically withholds 4% retención en la fuente (withholding tax on financial income, under DIAN Estatuto Tributario Art. 395).
This guide covers the exact calculation formulas, how Colombian rate conventions work, the 2026 rate environment, and how to compare CDTs across banks and digital platforms.
How CDT Interest Is Calculated
Colombian banks quote CDT rates in two ways:
EA (Efectiva Anual — Effective Annual Rate): The rate already incorporates compounding. Interest for any period is calculated directly:
Gross Interest = Principal × [(1 + EA)^(days/365) − 1]
NMV (Nominal Mensual Vencida — Nominal Monthly Rate, payable at end of month): A monthly nominal rate that must be converted before use. To find the EA equivalent: EA = (1 + NMV/12)^12 − 1
Once you have the gross interest using either convention, the net interest is:
Net Interest = Gross Interest × (1 − 0.04)
The bank retains 4% of gross interest and issues a certificate (certificado de retención) that you use in your annual Declaración de Renta as a tax credit.
Final balance at maturity = Principal + Net Interest
Worked Example: COP 50,000,000 / 12 Months / 13.5% EA
| Variable | Value |
|---|---|
| Principal | COP 50,000,000 |
| Term | 365 days (12 months) |
| Rate | 13.5% EA |
| Gross interest | COP 50,000,000 × [(1.135)^1 − 1] = COP 6,750,000 |
| Withholding tax (4%) | COP 6,750,000 × 0.04 = COP 270,000 |
| Net interest | COP 6,750,000 − COP 270,000 = COP 6,480,000 |
| Final balance at maturity | COP 56,480,000 |
| Effective net yield | COP 6,480,000 ÷ COP 50,000,000 = 12.96% net EA |
The effective net yield after withholding is 12.96% — which you can compare directly against alternatives (TES bonds, savings accounts, equity mutual funds).
The Colombian Rate Environment in 2026
The Banco de la República (BanRep) set its policy rate at a 23-year high of 13.25% in 2023 to combat inflation that peaked at 13.1%. By Q1 2026, the policy rate had declined to approximately 9.25% as inflation normalized toward the 3% target. CDT rates track the policy rate with a lag of 1–2 months.
Typical 2026 CDT rates for 90-day deposits:
- Traditional banks (Bancolombia, Davivienda, Banco de Bogotá): 10.5%–12.0% EA
- Cooperative/solidarity sector (Financoop, Cotelco): 11.0%–12.5% EA
- Digital/fintech banks (Nequi CDT, Lulo Bank): 12.0%–13.5% EA
Rates for 180-day and 12-month CDTs are typically 0.5%–1.5 pp higher than 90-day rates, reflecting the additional liquidity commitment.
4×1000 Tax (GMF) — What It Is and Whether It Applies
The Gravamen a los Movimientos Financieros (GMF) — colloquially called the 4×1000 — is a 0.4% transaction tax on financial debits. It applies when money moves between bank accounts. For CDTs specifically:
- Investment deposit (wire/transfer): 0.4% of the invested amount if coming from a taxable account. If your savings account is the exempted primary current account (exenta via Article 879), GMF does not apply.
- Maturity payment: 0.4% of the maturity balance if paid to a non-exempt account.
Many investors open their CDT directly at the same bank as their primary current account and keep both exempt to avoid the GMF. Verify your account’s exempt status with the bank before investing.
Provider Comparison: Banks, Cooperatives, and Fintech
| Provider type | Example institutions | Rate advantage | Fogafín coverage | Liquidity |
|---|---|---|---|---|
| Large banks | Bancolombia, Davivienda, Banco de Bogotá | Moderate (10.5%–12%) | Yes, up to COP 50M | None until maturity |
| Regional banks | Banco Agrario, GNB Sudameris | Slightly higher | Yes, up to COP 50M | None until maturity |
| Cooperativas / solidarias | Financoop, Cotrafa | Higher (11%–13%) | FOGACOOP, not Fogafín | None until maturity |
| Fintech/digital CDTs | Nequi, Lulo Bank, RappiPay | Highest (12%–14%) | Yes (via partner bank) | None until maturity |
Fogafín (Fondo de Garantías de Instituciones Financieras) insures deposits up to COP 50,000,000 per depositor per entity. If you hold COP 100,000,000 at a single bank, only half is insured — spread across entities to maximize coverage.
Cooperatives are supervised by the Superintendencia de Economía Solidaria (not the Superintendencia Financiera) and covered by FOGACOOP, a separate guarantee fund. Understand the difference before committing large capital to a cooperative-sector CDT.
CDTs vs Alternative Colombian Fixed-Income Instruments
| Instrument | 2026 yield (approx) | Liquidity | Tax treatment | Minimum |
|---|---|---|---|---|
| CDT 90 days (traditional bank) | 10.5%–12% EA | None until maturity | 4% withholding | COP 1,000,000 |
| CDT 12 months (digital bank) | 12%–14% EA | None until maturity | 4% withholding | COP 100,000 |
| TES (government bonds, 1-year) | ~10%–11% | Secondary market (variable) | 4% withholding | COP 1,000,000 (via broker) |
| Cuenta de ahorros (savings account) | 3%–6% EA | Immediate | 4% withholding | None |
| Fondos de inversión colectiva | 9%–12% EA (variable) | T+1 or T+3 | 4% withholding | COP 50,000 |
The CDT’s advantage is its fixed, locked-in rate for the entire term — in a declining-rate environment, locking a 13% EA CDT for 12 months before BanRep’s next rate cut is an explicit choice to preserve a high rate.
Early Withdrawal: What to Expect
CDTs are contractually locked until maturity. Early withdrawal (rescate anticipado) is at the bank’s discretion and typically involves:
- Full or partial loss of accrued interest (typically 30–50% forfeiture)
- A minimum lock-in period (usually 30 days) before any early withdrawal is permitted
- Formal written request process
Some digital platforms advertise "liquidity windows" or secondary market features for their CDTs. Verify the terms in the contract — not the marketing.
How to Use the Simúlalo CDT Calculator
Enter the principal (COP, USD, EUR, or the currency of your CDT), the annual nominal rate as EA, and the term in days. The calculator outputs:
- Gross interest — before withholding
- Withholding tax amount (4%)
- Net interest — what you actually receive
- Final balance at maturity
- Effective net yield (annualized) for comparison with other instruments
Run the calculator for 90-day, 180-day, and 12-month terms at the same rate to understand the compounding effect of rolling shorter-term CDTs versus committing to a full year.
Tax Planning: How the 4% Withholding Fits into Your Declaración de Renta
The 4% retención en la fuente withheld by the bank at CDT maturity is not a final tax — it is an advance payment on your annual income tax obligation. When you file your Declaración de Renta, the withheld amount appears as a deductible tax credit against your total income tax liability.
For declarantes in the second income bracket (approximately COP 85M–300M annual income), the marginal income tax rate is 28%. The 4% withholding covers only a fraction of the actual tax due on CDT returns — you will owe additional tax at settlement. For low-income investors who are below the declarante threshold, the 4% withholding is the effective final tax cost, and the net yield is as calculated.
The practical implication: high-income investors comparing a CDT (12% EA before 4% withholding = ~11.5% post-withholding but pre-renta) against a tax-exempt investment (such as a primary-residence mortgage interest deduction or a pension fund contribution with tax deduction) must account for the full marginal tax rate, not just the 4% withholding.