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iban-validator

An IBAN validator checks an International Bank Account Number for proper format and a valid mod-97 checksum — catching typos before money is sent to a wrong account. IBAN is the standard for cross-border bank transfers in Europe and 75+ countries; format is country-specific (German IBAN is 22 chars, UK is 22, Italy 27). The ZTools IBAN Validator checks: country code prefix, length per country, character set, and the mathematical mod-97 check digit calculation. Identifies the country, BBAN (basic bank account number), bank code, and branch. Pure client-side; no IBAN sent to any server.

Use cases​

Pre-transfer typo check​

About to wire money internationally? Validate the IBAN before submitting to your bank — catches typos that could send money to a stranger.

Vendor / supplier onboarding​

New international supplier provided an IBAN. Validate before adding to AP system; bad IBANs cause delayed/lost payments.

E-commerce checkout​

Real-time validation during checkout for SEPA direct debit / bank transfer. Catches typos before they cost the customer time.

Migrating data​

Importing customer / supplier records — bulk-validate IBANs to find dirty data.

How it works​

  1. Enter IBAN — With or without spaces. Tool normalises (removes spaces, uppercase).
  2. Format check — Country code (first 2 chars) → expected length and pattern lookup. Length must match exactly.
  3. Checksum — Mod-97 algorithm: rearrange chars, convert letters to numbers, compute mod 97. Result must be 1.
  4. Parse fields — Country, check digits, bank code, branch code, account number — each country has different layout.
  5. Result — Pass / fail + parsed components shown. Failed IBANs may indicate typo or wrong country.

Examples​

Input: DE89 3704 0044 0532 0130 00 (Germany sample)

Output: Valid — Germany, Bank: Commerzbank Cologne, Account: 0532013000.

Input: GB82 WEST 1234 5698 7654 32 (UK sample)

Output: Valid — UK, Bank: NatWest sort code 12-34-56, Account: 98765432.

Input: DE89 3704 0044 0532 0130 01 (typo last digit)

Output: INVALID — checksum fails. Likely typo in last digit.

Frequently asked questions​

What's an IBAN?

International Bank Account Number — standardised account ID for international transfers. ISO 13616. Includes country code + check digits + country-specific bank/account portion.

Why does the checksum matter?

Mod-97 algorithm catches single-digit typos (the most common error). Without checksum, a 1-character typo silently sends money to a different real account.

Is "valid" the same as "this account exists"?

No — checksum validation only confirms the format is mathematically correct. The account may not exist or may be closed. Only the destination bank can confirm.

Which countries use IBAN?

All EU + EEA, Switzerland, UK, Norway, Iceland, plus 50+ others (Israel, Saudi Arabia, UAE, Tunisia, Turkey, Pakistan, etc.). Notably NOT used in US, Canada, Australia, India.

How do US accounts work?

US uses ACH (domestic) or SWIFT/BIC + account number (international). No IBAN.

Is IBAN sufficient for an international wire?

In SEPA region (EU): IBAN alone often enough. Outside SEPA: need IBAN + BIC/SWIFT code of the destination bank. Always confirm with the recipient.

Tips​

  • Always validate IBAN before initiating a wire transfer — catches the cheapest-to-fix errors at the cheapest moment.
  • For UI input, normalise (strip spaces, uppercase) on blur — improves UX.
  • Display the formatted IBAN (with spaces every 4 chars) on output — easier for humans to verify.
  • For SEPA, IBAN + recipient name is enough; for non-SEPA, also collect BIC/SWIFT.
  • Bulk-validate vendor IBANs annually — bank mergers cause IBAN changes.

Try it now​

The full iban-validator runs in your browser at https://ztools.zaions.com/iban-validator — no signup, no upload, no data leaves your device.

Open the tool ↗

Last updated: 2026-05-06 · Author: Ahsan Mahmood · Edit this page on GitHub