how to calculate total effective cost cet

How to calculate CET without falling for the nominal rate trap

If the advertised rate looks too good, CET usually shows up to ruin the party — for good reason.

⚠️ Educational simulation. The CET uses Newton-Raphson to solve for the internal rate of return of the cash flow.

Loan amount

Number of installments

cetCalculator.meses

cetCalculator.nominalRate

% a.m.

Admin fee (one-time)cetCalculator.adminHint

cetCalculator.insurance

cetCalculator.upfrontFeescetCalculator.upfrontHint

cetCalculator.includeIof

Result

CET (annual)

50.59% a.a.

CET (monthly)3.4700% a.m.

cetCalculator.nominalPaymentR$ 559,13

cetCalculator.effectivePaymentR$ 609,13

Resolução CMN 3.517/2007 — CET mandatory disclosure. Newton-Raphson method.

Calculated in your browser. No financial data is transmitted.

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CET does the messy work of transparency

CET evaluates the full credit cash flow, including fees, IOF, insurance and the net amount effectively disbursed.
That is why comparing only nominal rates across lenders can lead to very poor decisions.

Comparisons that matter

Same nominal rate, different CET

Input: 2 propostas com taxa mensal parecida
Expected output: CET maior no contrato com mais tarifas

Shows why window-display rates can mislead.

Lower net disbursement

Input: Taxas embutidas no início
Expected output: CET sobe porque você recebe menos do que acha

Very common in supposedly “cheap” credit.

Full tool FAQ

What is CET and why is it required?

CET (Custo Efetivo Total) is a standardized annual rate that must be disclosed by all Brazilian banks for credit operations, as required by CMN Resolution 3.517/2007. It allows consumers to compare different loan offers on equal footing.

What is included in CET that is not in the nominal rate?

Why is CET always higher than the nominal rate?

How is CET calculated mathematically?

Can I compare CET across different loans?

Is the CET the same as the APR (Annual Percentage Rate)?

Why does this calculator use Newton-Raphson?

What if the calculator shows 'could not solve'?

Frequently asked questions

Is CET the same as the interest rate?

No. CET is a fuller measure of the cost of credit and is usually above the nominal rate.

If CET is higher, is the contract necessarily bad?

Not necessarily, but it must be compared with alternative offers and your real cash-flow capacity.