IBAN Validator — Check and Format Bank Account Numbers

Check whether an IBAN is valid before you send money or save it: the country, the length for that country, the account format and the mod-97 checksum. See it formatted in groups of four with the bank and branch code pulled out, validate a whole list at once, or generate test IBANs for your forms and payment tests. Nothing leaves your browser.

Runs in your browserUpdated

Your data never leaves your computer. All processing happens 100% locally in your browser.

How to use the IBAN Validator

  1. Type or paste an IBAN — spaces, dashes and lowercase are fine. The result updates as you type.
  2. Read the verdict: the country, whether the length and format match that country, and whether the check digits are right.
  3. Copy the IBAN in its standard printed format (groups of four) or electronic format (no spaces), and see the bank and branch code.
  4. To check many, use Check a list; to test a form or payment sandbox, use Test IBANs.

How IBAN validation works

An IBAN starts with a two-letter country code and two check digits, followed by the domestic account number (the BBAN). Every country has a fixed length — 22 characters for Germany, 27 for France, 18 for the Netherlands — and a fixed pattern of letters and digits.

The check digits come from the ISO 7064 mod 97-10 algorithm: move the first four characters to the end, turn every letter into a number (A = 10 … Z = 35) and divide by 97. A valid IBAN always leaves a remainder of 1. This catches all single-character typos and almost all swapped neighbors.

What a valid IBAN does — and doesn’t — prove

A valid IBAN has the right shape and checksum, so it is very likely typed correctly. It does not prove that the account exists, is open or belongs to the person you expect — only the bank (or a confirmation-of-payee service) can confirm that. For card numbers, see the Credit Card Validator.

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Tools that pair well with the IBAN Validator

  • Random Number Generator — Generate random numbers (with or without duplicates), pick winners from a list, shuffle names, split groups into teams, flip coins and roll dice — using your browser’s cryptographically secure randomness.
  • Mock Data Generator — Create up to 10,000 rows of realistic test data — users, products, orders, addresses, companies or nested API records — or build your own schema.
  • Regex Tester — Type a pattern and watch matches highlight live in your test text.
  • Number Base Converter — Type a number in any base and see it in all the others instantly.

Frequently asked questions

How can I tell if an IBAN is valid?
Check that the length matches the country, the characters follow that country’s format, and the mod-97 checksum leaves 1. This validator does all three as you type.
Does a valid IBAN mean the account exists?
No. Validation proves the number is well-formed and very likely typed correctly. Only the bank can confirm the account exists and who owns it.
Should an IBAN be written with spaces?
Printed IBANs use groups of four characters for readability; electronic forms and payment files use the IBAN without spaces. Both refer to the same account.
Are the test IBANs real?
They have a valid structure and checksum but random account numbers, so they are meant for testing forms and payment sandboxes — never use them for real payments.
Can I install IBAN Validator as a web app and use it offline?
Yes. IBAN Validator is an installable web app (PWA) — installed from your browser, not downloaded from an app store. Click Install app at the top of this page in Chrome or Edge (Windows, macOS, Linux, ChromeOS) or on Android, use Share → Add to Home Screen on iPhone and iPad, or File → Add to Dock in Safari 17+ on a Mac. It then opens in its own window with its own icon, and because it runs entirely in your browser it keeps working offline. Firefox on desktop can’t install web apps. How installing works.

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