Itaú Bank Account Validator

Itau account numbers: COMPE 341 and the structure of agency, account and check digit

Itau Unibanco accounts use the layout agencia + conta + DV, where the agency has 4 digits, the account has 5 or 6 digits and the check digit (DV) is 1 numeric digit. The COMPE (Comunicacao Interbancaria) code that identifies the bank in the Brazilian Payments System is 341, the historical Itau code preserved after the 2008 merger with Unibanco. Branch numbers do not carry an additional DV in the public-facing format used on cards, statements and Pix copia-e-cola receipts, although internal Itau systems carry a separate branch check.

Itau (Itau Unibanco Holding) is the largest private bank in Latin America by total assets, with roughly R$ 2 trillion on the balance sheet, more than 4,500 branches and tens of millions of customers across retail, private and corporate segments. The bank operates two main consumer brands: the super app Itau for traditional account holders and Iti, the standalone digital wallet launched in 2019 to compete with Nubank and PicPay.

The Itau check-digit algorithm: modulo 10 simplified

Unlike CPF, CNPJ and most other Brazilian documents that use modulo 11, Itau uses a modulo 10 scheme close to the Luhn algorithm. The procedure for a 5-digit account plus DV is:

• Concatenate agencia (4) + conta (5) into a 9-digit string.
• Multiply each digit, from right to left, by alternating weights 2, 1, 2, 1, 2, 1, 2, 1, 2.
• For every product greater than 9, sum its digits (so 14 becomes 1+4 = 5).
• Add all results, take modulo 10, and subtract from 10. If the subtraction yields 10, the final DV is 0.

This is exactly the technique applied to credit-card PANs in ISO/IEC 7812. Worked example for agency 0911 and account 12345: the weighted, digit-summed sequence is 0,9,2,1,2,3,8,5,1, total 31; 31 mod 10 = 1; DV = 10 - 1 = 9. Full account: 0911 / 12345-9.

Itau vs Bradesco vs Banco do Brasil: distinct algorithms, same family

Each large Brazilian bank publishes its own check-digit algorithm. Itau uses modulo 10 with Luhn-style digit folding, Bradesco uses modulo 11 with weights 2 to 7 and a special letter P for two residues, Banco do Brasil uses modulo 11 with letter X, Caixa uses modulo 11 with a region prefix and Santander uses its own modulo 11 variant. The common anti-pattern is hardcoding one algorithm and treating every bank account the same — the result is false negatives that block legitimate payments.

Where Itau accounts are still validated client-side

• Payroll onboarding at HR systems that pay employees by credit in conta corrente.
• Boleto registration on Itau cash management for B2B receivables.
• Direct debit (debito automatico) authorizations for utilities, gyms and SaaS subscriptions.
• Legacy TED / DOC transfers, although DOC was extinguished in February 2024 by Bacen Resolution BCB 281/2022 and TED for PF migrated almost entirely to Pix.
• OFX statement parsers that import bank statements into accounting and personal-finance apps.

In 2026, the typical end-user moves money on Itau via Pix using a chave (CPF, email, phone or random UUID), so the public exposure of the agencia + conta + DV triplet is shrinking. It still matters for cash management, salary credits, judicial deposits and any integration that uses Open Finance Phase 2 payment initiation against Itau.

Implementing Itau validation in Node and Python

function itauDV(ag, conta) {
  const s = (ag + conta).split('').reverse()
  let sum = 0
  for (let i = 0; i < s.length; i++) {
    let p = parseInt(s[i], 10) * (i % 2 === 0 ? 2 : 1)
    if (p > 9) p = Math.floor(p / 10) + (p % 10)
    sum += p
  }
  const dv = (10 - (sum % 10)) % 10
  return dv
}
// itauDV('0911', '12345') === 9

For Python, the npm package bancos-brasileiros and the Python brazilian-bank-validator both implement Itau, Bradesco, BB and Caixa with the same interface. Always prefer a maintained library over a one-off snippet — bank specs change quietly (Itau extended retail accounts from 5 to 6 digits for some segments in 2019) and the libraries track these revisions.

FAQ

Does Itau accept Pix in 2026? Yes. Pix has been mandatory for full members of the Brazilian Payments System since November 2020. Itau exposes Pix on the app, internet banking, ATM and Itau Empresas API. Transfers settle in under 10 seconds, 24/7, and are free for natural persons.

Is TED still available between Itau accounts? Yes for natural persons, with the same business-day window (until 17:00). For corporate accounts, Itau strongly nudges Pix because TED fees and operational windows are no longer competitive after the Bacen 2024 reforms.

Is the Itau check-digit algorithm public? The Banco Central publishes the COMPE catalog and Bacen Circular 3,461 references the agency/account scheme, but the precise DV formula has historically been distributed via Itau cash-management manuals (Bradesco does the same). The community-maintained bancos-brasileiros repository reverse-engineered it more than a decade ago and matches Itau confirmation receipts.

What about Iti accounts? Iti operates on the same Itau ledger (COMPE 341) using an internal agency, so to receive a Pix or TED you can use any chave; for legacy transfers the Iti app shows the underlying agencia + conta + DV, which validates with the same algorithm.

Does this validator query Itau servers? No. The math runs entirely in your browser. Confirming ownership requires Open Finance consent or a contracted bank-verification API such as idwall, Unico or Caf.