IBAN reference
IBAN format & example by country
Every country that issues IBANs uses a fixed length and a country-specific BBAN structure defined by ISO 13616. Pick a country to see its full format spec and a MOD 97-valid sample IBAN for testing.
How IBAN country formats work
An IBAN always starts with a 2-letter ISO 3166 country code, followed by 2 check digits, and then the BBAN — the country-specific part. The length and the BBAN structure differ per country but are fixed within each country. For example, German IBANs are always 22 characters; Belgian IBANs are always 16.
The check digits are computed with the MOD 97-10 algorithm so that any single-digit or swap error is caught. The format pages linked above break each country's BBAN into its fields; the example pages provide a synthetic, MOD 97-valid IBAN for integration testing.
Need to validate a real IBAN instead of browsing formats? Use the IBAN validator.