IBAN validator
Validate an IBAN online — country, length and mod-97 check digits, entirely in your browser.
Runs 100% in your browser100% in your browser — your IBAN is never uploaded. Checksum check only — verify the account with the recipient before sending money.
How to validate an IBAN
- Enter an IBAN. Paste the IBAN with or without spaces.
- Validate. We check the country, length and mod-97 check digits locally.
- Review. See whether it is valid and its decoded parts.
How an IBAN is put together
The International Bank Account Number wraps a country's existing account number in a standard envelope so cross-border payments route correctly across the 70-plus countries that use it. The shape is always the same: a two-letter country code, two check digits, then the country-specific BBAN (the domestic bank and account number). The total length is fixed per country — a German IBAN is always 22 characters, a UK one 22, a French one 27 — so a value of the wrong length for its country code is invalid on sight, before any maths.
The mod-97 check, in plain terms
The two check digits come from the mod-97 algorithm (ISO 7064). To verify: move the first four
characters to the end, replace each letter with two digits (A=10, B=11, …
Z=35), and treat the result as one big integer — a valid IBAN leaves remainder 1
when divided by 97. That single test catches virtually every single-character typo and any swap of two adjacent
digits, which are the mistakes people actually make copying an account number. Validating before you save or
send turns a silent misroute into an instant "that's not right".
What a pass does and doesn't mean
A valid IBAN is structurally correct — the right country, length and check digits — and that's the whole of what arithmetic can prove. It does not confirm the account is open, belongs to who you think, or has funds; only the bank knows that. This tool runs every check locally in your browser, so a sensitive account number is never transmitted or stored. To validate the bank's routing code in the same payment, use the SWIFT/BIC lookup.
Frequently asked questions
- It verifies the country code, the exact length for that country, and the ISO 7064 mod-97 check digits — the same maths banks use to catch typos in an IBAN.
- No. Validation confirms the IBAN is correctly formed and free of typos. It does not contact any bank or confirm the account is real or open.
- No. The entire check runs in your browser with no network calls, so your banking details never leave your device.
- Usually a single mistyped character, the wrong length for the country, or an unsupported country code. The error message tells you which.
- No — by design. This is a validator only; it never produces account numbers.