CDT Calculator — Net Return at Maturity

Easily estimate your CDT returns with our reliable Bancolombia CDT simulator tailored for Colombia’s market.

  • Instant result
  • No sign-up
  • Visible assumptions
  • Deterministic calculation

In 30 seconds: Accurately calculate your CDT investment growth and maximize your returns with ease. Deterministic calculation with auditable formulas. The result is indicative — adjust the assumptions to reflect your real operation.

Methodology

Capitalization factor = (1 + EAR / 100)^(days / 365)

Final gross amount = Capital × factor

Gross interest = Final gross − Capital

Withholding = Gross interest × (withholding % / 100)

Net interest = Gross interest − Withholding

Final net amount = Capital + Net interest

Annualized net return = ((Final net / Capital)^(365 / days) − 1) × 100

Variables

Capital
Amount deposited at CDT opening (in local currency).
Term in days
CDT duration. Common terms: 30, 60, 90, 180, 360, 540 days.
Effective Annual Rate (EAR)
Annualized rate published by the bank — distinct from nominal or monthly.
Withholding tax
% bank withholds on interest. Default 4% Colombia (DIAN art 379 ET).

Practical example

Capital $5,000,000 COP, 180 days at 11% EAR (Bancolombia).

Factor: (1 + 0.11)^(180/365) = 1.0521.

Final gross: 5,000,000 × 1.0521 = $5,260,750 COP.

Gross interest $260,750. Withholding 4%: $10,430.

Net interest: $250,320. Final net: $5,250,320.

Period return: 5.01% / annualized net ~10.3%.

Interpretation

CDTs are fixed-income — the bank guarantees the rate over the entire term regardless of market moves.

4% withholding applies only in Colombia. Other countries: adjust manually. Pension/exempt accounts: 0%.

Breaking a CDT before maturity usually penalizes with ~0% rate over elapsed days.

Compare net EAR vs expected inflation: 11% EAR with 8% inflation = real ~3% return.

Assumptions and limitations

  • Effective annual capitalization scaled to days. Some banks publish monthly capitalization.
  • Excludes opening fees. Most banks don't charge for retail CDTs.
  • Excludes auto-renewal. If you renew, the cycle resets with the rate at that moment.
  • Withholding assumes Colombia (4%); edit for other jurisdictions.

When to use this calculator

  • To compare offers from Bancolombia, Davivienda, BBVA, Itaú and digital banks.

  • To decide between CDT, mutual fund, or savings account.

  • To calculate how much to invest today to reach a target final amount.

  • To validate what the bank credits at maturity — demand a breakdown if it differs.

  • To compare different terms: 360d at 11% vs 90d at 9% × 4 renewals.

Common mistakes

  • Confusing EAR with nominal or monthly rate. EAR 11% is NOT 11/12 = 0.92% monthly.

  • Ignoring withholding. The amount the bank credits is always net post-tax.

  • Taking the published rate without verifying it's still in force at opening.

  • Believing breaking the CDT pays prorated interest.

  • Comparing CDTs of different terms without annualizing the return.

Industry use cases

Individual investor (Colombia)

$10M COP at 180 days at 11% EAR: net interest ≈ $521k COP. Net annualized ~10.7%.

SME cash surplus

$50M COP at 90 days at 9.5% EAR → $1.13M net interest. Liquidity preserved + return captured.

Tax-exempt account (AFC, voluntary pension)

$20M COP at 360 days at 11% EAR with 0% withholding: full $2.2M COP net interest.

CDT vs mutual fund

CDT 180d at 10.5% net ~5%. Fund expected 12% with 1.5% fee → real ~10%. CDT wins on certainty.

Auto-renewal vs active reinvestment

$5M COP auto-renewed 12mo at 9% may leave $80k less than manually reinvesting at each maturity.

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Financial disclaimerIndicative result — not professional financial advice. Consult a specialist before making investment or credit decisions.

View methodology

Calculator guide

What it calculates and who it is for

This calculator projects the return of a CDT (term deposit certificate): from the principal, the term in days and the effective annual rate, it computes the period's interest, the applicable withholding tax, the net final amount and the equivalent net annualized rate.

Use it to compare CDT offers across institutions and terms with one uniform criterion — the effective annual rate — and to know, before committing, how much money you will actually receive at maturity after withholding. The result is indicative and does not constitute financial advice.

Inputs

Principal
The amount you deposit when opening the CDT, in your currency. It stays locked until maturity.
Term (days)
The deposit's duration in days: 90, 180 and 360 are common terms, but any number of days works.
Effective annual rate (% E.A.)
The rate institutions advertise for CDTs: the compound return equivalent to one year. It is the correct figure for comparing offers.
Withholding (%)
The withholding tax percentage applied to earned interest (4% by default, editable to your situation).

Results you get

Periodic rate for the term
The effective annual rate converted to your CDT's exact term through compounding — not a linear proportion.
Gross interest
What the principal earns over the term before withholding.
Withholding tax
The amount withheld on interest: deducted from your payout, not from principal.
Net interest and final amount
Interest after withholding and the total you receive at maturity: principal plus net interest.
Net period return
Net interest as a percentage of principal over the CDT's term.
Net annualized rate
The net return re-expressed as an effective annual rate: the number comparable against other savings alternatives.

Methodology and assumptions

Periodic rate % = ((1 + E.A. ÷ 100)^(days ÷ 365) − 1) × 100

Gross interest = Principal × Periodic rate ÷ 100

Withholding = Gross interest × Withholding % ÷ 100

Net interest = Gross interest − Withholding; Final amount = Principal + Net interest

Net annualized rate % = ((1 + Net return ÷ 100)^(365 ÷ days) − 1) × 100

Converting the effective annual rate to the term uses compounding (powers), not linear proportion: a 9.5% E.A. over 180 days does not yield half of 9.5%, but the 4.58% that results from compounding. That is the correct financial convention for effective rates.

Worked example

Hypothetical example for illustration. The numbers reproduce exactly when entered into the calculator on this page.

Worked example: a $10,000,000 COP CDT for 180 days at 9.5% E.A. with 4% withholding.

Periodic rate: ((1 + 0.095)^(180 ÷ 365) − 1) × 100 = 4.577%.

Gross interest: $10,000,000 × 4.577% = $457,722.

Withholding: $457,722 × 4% = $18,309.

Net interest: $439,413. Final amount at maturity: $10,439,413.

Net return for the half-year: 4.39%. Net annualized rate: 9.11% E.A. — the number to compare against another CDT, a fund, or any alternative expressed in annual effective terms.

How to interpret the result

Always compare net annualized rates: two CDTs with the same advertised E.A. but different terms deliver different amounts, and withholding makes the net annualized rate lower than the advertised E.A. The net annualized figure puts all offers in the same unit.

The term is a liquidity commitment: the example's return requires locking the principal for 180 days. Before choosing the longer term for a few extra rate points, weigh the odds of needing the money earlier.

To judge the real return, compare it against your country's inflation over the same period: a CDT protects nominal principal, but purchasing power depends on the gap between your net rate and inflation.

Limitations and when not to use it

  • Withholding is a tax prepayment, not the final tax: your ultimate tax situation depends on your filing. The applicable percentage can vary with your profile.
  • It does not model CDTs with periodic interest payouts (monthly or quarterly): the calculation assumes a single payment at maturity.
  • It does not include automatic rollovers or interest reinvestment across successive periods.
  • Real conditions (rate, withholding, early-redemption penalties) are those of your contract with the institution: verify the binding offer before opening.
  • Do not use it to compare against risk instruments (stocks, variable funds): a CDT is fixed income, and the right comparison is against alternatives of the same risk profile. It does not constitute financial advice.

From theory to calculation

The calculator on this page runs with your numbers — no forms, no login. Scroll up and try it.

Try the calculator

Frequently asked questions

1Why isn't the 180-day rate half the annual rate?
Because the effective annual rate is compound: converting it to a shorter term uses powers, not proportions. Half of 9.5% linearly would be 4.75%; the correct conversion gives 4.58% — the difference is the compounding effect.
2Is the withholding deducted from my principal?
No: it applies only to earned interest. Your principal returns in full; what shrinks is the interest you receive, and that withholding is a prepayment of your income tax.
3What if I need the money before maturity?
CDTs are term deposits: early redemption depends on the institution's conditions and usually carries a penalty or is unavailable. If you foresee needing liquidity, consider short terms or laddering several CDTs with staggered maturities.
4How do I compare a 90-day CDT against a 360-day one?
With the net annualized rate the calculator returns for each: re-expressing both net returns in equivalent annual terms puts the comparison in the same unit, leaving only liquidity to weigh.
5Can I use this calculator for deposits in other countries?
Yes, as long as your instrument pays at maturity and its rate is expressed as an effective annual rate: adjust the withholding to your jurisdiction's percentage, or set it to zero if none applies.

Last updated: July 19, 2026

View methodology

How this simulator was reviewed

What you'll see, what it prevents, and where you shouldn't trust it

Every simulator on Simúlalo ships with the same editorial structure: two hypothetical worked examples with numbers, the errors it helps you avoid, the model's declared limitations, and a visible financial disclaimer. The review is signed and dated.

Hypothetical caseCase A

Investor in Colombia placing $10M COP at 180 days and comparing two rates

An investor places $10,000,000 COP in a CDT. Rate A: 11% effective annual at 180 days. Rate B: 10.5% effective annual at 360 days. The calculator shows: Rate A generates approximately $526,820 gross at maturity; Rate B generates $1,050,000 at the 360-day maturity. However, option A allows renewal at the new rate at maturity — useful if rates rise. Decision: the choice depends on rate expectations; to diversify duration, split the amount across two terms.

Illustrative figures. Does not represent a real company or an investment recommendation.

Hypothetical caseCase B

Net return comparison before and after withholding tax

An investor places $5,000,000 COP at 90 days with 10.8% effective annual rate. Gross return at maturity: approximately $135,000. If withholding tax of 7% applies on the return (illustrative rate that varies by regime), net drops to approximately $125,500. Decision: when comparing CDTs, always look at net return after withholding and after taxes per your regime. For specific situations validate with an accountant.

Illustrative figures. Does not represent a real company or an investment recommendation.

Common mistakes it helps you avoid

Things a team or decision-maker might assume that this simulator forces you to verify before committing.

  • Comparing effective annual rate with nominal rate without converting. A 11% nominal can yield 11.5% effective depending on compounding frequency.
  • Forgetting withholding tax. In Colombia, CDT returns are subject to withholding that varies by tax regime and amount.
  • Auto-renewing without comparing rates. Some banks renew at maturity at the prevailing rate, which may be lower than the initial.
  • Using the CDT as emergency liquidity. Early withdrawal penalty or impossibility of withdrawal means a CDT does not substitute a liquid emergency fund.

Model limitations

What the simulator does not do, and where you need a professional or a specialized tool.

  • Does not query real rates from Colombian banks or other jurisdictions. You declare the rate at the start.
  • Does not apply withholdings automatically. For exact net calculation, consult the tax regime applicable to your situation.
  • Does not project inflation. Real return (return − inflation) can be zero or negative if inflation exceeds the rate.
  • Does not replace a bank quote or investment advice. It is a mathematical estimate of gross return.

When NOT to use this simulator

Don't use this calculator as an investment recommendation. Comparing CDTs requires also evaluating issuing entity risk, deposit insurance coverage in your country (Fogafín in Colombia, IPAB in Mexico, FGD in Spain), your liquidity horizon, and your tax regime. For decisions that move significant capital, consult a registered financial advisor in your jurisdiction.

Financial notice

Results are illustrative estimates and do not constitute financial, tax, accounting, or legal advice. Use the results as a reference point and validate important decisions with a certified professional.

Editorial review

Reviewed by the Simúlalo editorial team

This simulator was reviewed by the people listed below before being published. The review covers the declared formula, the model's assumptions, the explicit limitations, and the absence of unsupported financial claims.

They are part of the Simúlalo editorial team, focused on building financial tools that are clear, educational, and easy to interpret.

Last updated: We update this page when the methodology, sources used, or simulator structure change.

This tool uses standard financial formulas and user-supplied data. To explain concepts like rates, credit, risk, or cash flow we consult public and official sources (Banxico, SAT, CONDUSEF, CNBV, Banco de España, IFRS, BIS, among others). Simúlalo is not affiliated with, sponsored by, or endorsed by these institutions.