Netherlands IBAN validator
How the IBAN format works
- Format
- NL + 2 check digits + 4-letter bank code + 10-digit account number (18 chars)
- Example
- NL91ABNA0417164300
Things to watch for
- 18 characters total
^NL[0-9]{2}[A-Z]{4}[0-9]{10}$A Dutch IBAN is 18 characters — shorter than most European formats: “NL”, two check digits, a 4-letter bank code, and a 10-digit account number, with no separate branch-code block at all. That 4-letter bank code isn’t a random label; it’s the same identifier your bank uses in its BIC, just without the country prefix and branch suffix — recognizing it is often how a Dutch banking form or invoice tells you which bank an IBAN belongs to at a glance. Anyone paying a Dutch supplier, receiving a SEPA transfer, or filling in an international payment form that expects “NL” plus 16 more characters needs the bank-code and account-number blocks in exactly the right order.
How this validator works
This tool checks the “NL” prefix, confirms the bank-code block is 4 letters, and the account-number block is 10 digits, then runs the real mod-97 checksum (ISO 7064) Dutch banks use to generate a valid IBAN — entirely in your browser, nothing sent to a server, no signup, result the moment you stop typing.
What a pass doesn’t tell you
A pass confirms the 18 characters are correctly formed and internally consistent — not that the account is open, active, or belongs to the person you expect. This tool doesn’t resolve the 4-letter bank code to an institution name and never contacts a bank or De Nederlandsche Bank. If a Dutch IBAN fails, check first whether a letter in the bank-code block was mistaken for a similar-looking digit, or vice versa — that boundary between letters and digits is the one place a Dutch IBAN commonly gets mistyped.
Scope: Dutch IBAN structure and mod-97 checksum validation only — not payment processing, bank-name lookup, or confirming an account is active, none of which a client-side check can establish. Use this validator to catch a typo before a transfer fails; use your bank to confirm the account itself.
Content last reviewed 2026-07-07.
IBAN FAQ
What are the two blocks inside a Dutch IBAN, after the country code and check digits?
Just two: a 4-letter bank code and a 10-digit account number, making 18 characters total — for example NL91ABNA0417164300. There's no separate branch code, which keeps the Dutch format notably shorter and simpler than many of its neighbors.
Is the 4-letter bank code the same code my bank uses elsewhere, like in its BIC?
Yes — the 4 letters at the start of the BBAN are the same bank identifier that appears in the bank's SWIFT/BIC code, just without the country and branch suffix. It's not an arbitrary IBAN-only label.
Does this tool confirm which bank the 4-letter code belongs to?
No. It checks that the code is 4 letters in the right position and that the whole IBAN passes the mod-97 checksum — it does no bank-name lookup and never contacts a bank or De Nederlandsche Bank.