Ireland IBAN Format (IE) — Structure, Length & Validator

The Irish IBAN (Ireland IBAN) is used for all electronic bank transfers within Ireland and across the SEPA zone. Ireland adopted the IBAN standard as part of its SEPA transition, and Irish IBANs have a distinctive structure that includes an alphabetic bank identifier, making them immediately recognisable among European account numbers.

Irish IBAN at a Glance

• Country code: IE
• Total length: 22 characters (always)
• Format: IEkk bbbb cccccc aaaaaaaa
• BBAN length: 18 characters
• Currency: Euro (EUR)
• SEPA member: Yes

Irish IBAN Structure Explained

An Irish IBAN has four components packed into exactly 22 characters:

1. Country Code, IE (2 characters)

The ISO 3166-1 alpha-2 code for Ireland. Every Irish IBAN begins with IE. This never changes and is always two uppercase letters.

2. Check Digits, kk (2 digits)

Two decimal digits computed via the MOD-97 algorithm over the full BBAN. They catch transcription errors and are set when the account is opened. A valid Irish IBAN always produces a remainder of 1 when the MOD-97 check is applied.

3. Bank Identifier, bbbb (4 letters)

A 4-character alphabetic code that identifies the bank. This is derived from the bank's BIC (SWIFT) code. Common Irish bank identifiers include:

• AIBK, AIB (Allied Irish Banks)
• BOFI, Bank of Ireland
• IPBS, permanent tsb
• ULSB, Ulster Bank Ireland (withdrawn from the Irish market; accounts closed)

The presence of letters inside the IBAN (after the country code) is a defining feature of Irish IBANs and distinguishes them from most continental European IBANs which use only digits in the BBAN.

4. Sort Code, cccccc (6 digits)

Ireland's legacy 6-digit sort code, embedded directly in the IBAN. Sort codes identify the specific branch or payment processing centre within the bank. For example, AIB Grafton Street Dublin has a different sort code than AIB Cork.

5. Account Number, aaaaaaaa (8 digits)

The 8-digit account number at the branch identified by the sort code. If the original account number was fewer than 8 digits, it is left-padded with zeros.

Real Irish IBAN Example

IE29 AIBK 9311 5212 3456 78

• Country: IE
• Check digits: 29
• Bank identifier: AIBK (AIB)
• Sort code: 931152
• Account number: 12345678

In electronic format (no spaces): IE29AIBK93115212345678

How Irish IBAN Validation Works

Validating an Irish IBAN involves these sequential checks:

1. Country code: First two characters must be IE.
2. Length: Total character count (spaces removed) must be exactly 22.
3. Character types: Positions 3–4 are digits; positions 5–8 are uppercase letters; positions 9–22 are digits.
4. MOD-97: Rearrange characters, convert letters to numbers (A=10…Z=35), compute the full numeric string modulo 97. The result must be 1.

The ibanchecker.cash validator runs all four checks instantly. Paste any Irish IBAN to see the bank name, BIC, sort code, and a full BBAN breakdown.

Common Irish IBAN Mistakes

Lowercase Bank Identifier

Some systems transmit the bank identifier in lowercase (aibk instead of AIBK). The IBAN standard requires uppercase letters. Strip and uppercase the entire IBAN before validation or transmission.

Missing Leading Zeros in the Account Number

An account number shown as 1234567 (7 digits) on an Irish bank statement should be zero-padded to 01234567 (8 digits) when constructing the IBAN. Dropping the leading zero produces a 21-character IBAN that fails the length check.

Confusing Sort Code Position

In Irish IBANs, characters 9–14 (after the bank identifier) are the sort code, not part of the account number. Systems expecting a fully-numeric BBAN will incorrectly split the IBAN at the wrong boundary.

Ireland, SEPA, and the Euro

Ireland is a founding eurozone member and a full SEPA participant. All domestic Irish transfers use the IBAN. For SEPA Credit Transfers and SEPA Direct Debits within the SEPA zone, the IBAN alone is sufficient, no BIC is required. For payments outside SEPA, the bank's BIC must accompany the IBAN. Look up any Irish bank's BIC using the ibanchecker.cash SWIFT directory.

Validating Irish IBANs in Bulk

Accounts payable teams and payroll processors working with Irish suppliers or employees can validate multiple IBANs at once with the ibanchecker.cash bulk checker. Upload a CSV or paste up to 100 IBANs and get bank name, BIC, and error details for each row in seconds.

Sources & References

• SWIFT IBAN Registry — Official IBAN country format specifications
• ISO 13616 — IBAN international standard
• EPC SEPA Participants — Ireland in SEPA scheme registers
• Central Bank of Ireland — Payment system oversight and SEPA implementation
• ECB TARGET2 — Eurozone payment infrastructure used by Irish banks

Last updated: June 2026