IBAN stands for International Bank Account Number. It is a standardized format used in most of Europe and the Middle East that encodes the country, check digits, bank, and account number in a single string of up to 34 characters.

How is an IBAN validated?

An IBAN must start with a 2-letter country code and 2 check digits, match the expected length for its country, and pass the mod-97 check: when the first 4 characters are moved to the end, letters are converted to numbers (A=10..Z=35), and the result is divided by 97, the remainder must equal 1.

What is a SWIFT or BIC code?

A SWIFT/BIC (Bank Identifier Code) is 8 or 11 characters and identifies a specific bank for international wires. The structure is 4-letter bank code + 2-letter country code + 2-character location code + optional 3-character branch code (XXX or omitted means the primary office).

What is a US routing number?

A US ABA routing number is a 9-digit code that identifies a bank or credit union for ACH and wire transfers. It has a built-in checksum: 3×(d1+d4+d7) + 7×(d2+d5+d8) + (d3+d6+d9) must be divisible by 10.

Does this tool confirm the account exists or who owns it?

No. The Bank Account Number Checker only validates formatting and structure. It does not contact any bank, look up account holders, check balances, or confirm that an account exists. Always verify payment details directly with the recipient before sending money.

Are my inputs uploaded anywhere?

No. Every check runs entirely in your browser. Account numbers, IBANs, and SWIFT codes never leave your device.

Why does my IBAN have spaces when displayed?

Spaces every 4 characters are a display convention to make IBANs readable. They must be removed before validation and transmission.

Common Bank Account Entry Errors

Transposed digits

Swapping two adjacent digits is the most common typo. Mod-97 (IBAN) and the ABA checksum (US routing) catch almost every transposition — which is exactly what they were designed for.

Copy-paste whitespace and characters

Pasting from a PDF or email often pulls in non-breaking spaces, line breaks, or zero-width characters. Always normalize (strip whitespace, uppercase) before validating — which Bank Account Number Checker does automatically.

The wrong identifier in the wrong field

A SWIFT code pasted into the IBAN field is a classic. So is a sort code mistaken for a routing number. The format checks here will reject these immediately because lengths and character sets don't match.

Missing or wrong country prefix

Dropping the 'GB' or typing 'DE' instead of 'NL' breaks IBAN length checks. The country code is structural — there's no graceful fallback if it's wrong.

Try the tool

Bank Account Number Checker

Validate IBANs, SWIFT/BIC codes, US routing numbers, and country-specific bank account formats.

Open Bank Account Number Checker

Frequently asked questions

Nothing automatic — the checksum catches the most common errors but not all. For high-value payments, confirm the recipient's details out-of-band before sending.

Jun 3, 20265 min read