IBAN Format by Country — Complete Reference Guide

The International Bank Account Number (IBAN) is a standardized system for identifying bank accounts across national borders. Originally developed for European transactions, IBAN has been adopted by over 80 countries worldwide. This guide provides the complete IBAN format, length, and example for every participating country.

What Is an IBAN?

An IBAN is an internationally agreed-upon format defined by ISO 13616. It was created to reduce errors in cross-border payments by providing a consistent structure that machines and humans can both validate.

Every IBAN contains the same core components, regardless of country:

• Country code — two letters (ISO 3166-1 alpha-2)
• Check digits — two digits calculated using MOD-97 (ISO 7064)
• BBAN — Basic Bank Account Number (country-specific format containing bank code, branch code, and account number)

IBAN Structure

The maximum IBAN length is 34 characters. The shortest IBANs are 15 characters (Norway), and the longest are 34 characters (Saint Lucia). Each country has a fixed IBAN length — all IBANs from the same country are the same number of characters.

IBAN Formats by Country

The table below lists every country that uses IBAN, organized by region. The Format column uses: n = digit, a = letter, c = alphanumeric.

How to Validate an IBAN

The MOD-97 validation algorithm is straightforward:

1. Remove spaces from the IBAN
2. Move the first four characters (country code + check digits) to the end
3. Convert all letters to numbers: A=10, B=11, C=12, ... Z=35
4. Calculate the remainder when dividing the resulting number by 97
5. If the remainder is 1, the IBAN is valid

Worked Example

Common IBAN Errors

• Wrong length — each country has a fixed IBAN length; adding or removing a digit invalidates it
• Transposed digits — swapping two adjacent digits changes the check digit calculation
• Wrong country code — using the wrong two-letter country prefix
• Including spaces in transmission — IBANs are printed with spaces for readability, but electronic systems must strip them
• Lowercase letters — IBANs should always use uppercase letters

Frequently Asked Questions