IBAN Validator

Paste an IBAN to see whether it passes the ISO 7064 mod-97 checksum, whether its length matches the country it claims, and how it breaks down into country code, check digits, and the basic bank account number (BBAN). It recognizes the registered length for around 70 countries. Everything runs in your browser - no account number is sent anywhere or stored.

Security

Check an International Bank Account Number with the official mod-97 checksum, confirm it's the right length for its country, and see the parts broken out. It runs entirely in your browser - nothing is sent anywhere.

IBAN

How IBAN validation works

An IBAN is checked with the ISO 7064 mod-97-10 algorithm. The first four characters (country code plus two check digits) are moved to the end, every letter is replaced by a number (A=10, B=11, up to Z=35), and the resulting big number is taken modulo 97. A valid IBAN leaves a remainder of exactly 1. This catches the vast majority of typos and transposed digits before a payment is ever submitted.

Why length matters

Each country fixes the exact length of its IBANs - 22 for the UK and Germany, 27 for France, 18 for the Netherlands, and so on. The check digits can pass while the length is still wrong, so the tool checks the length against the registered value for the country code and tells you both numbers when they don't line up.

What it doesn't check

A valid IBAN means the number is well-formed, not that the account exists or can receive money. The checksum and length are structural checks only. Confirming an account is real and open requires the bank, which no client-side tool can do.