Denmark IBAN validator

A Danish IBAN is 18 characters, entirely numeric after the country code: “DK”, two check digits, a 4-digit bank code, and a 10-digit account number, run together with no spaces in the machine-readable form. That 4-digit bank code carries over the registreringsnummer Danish account holders already recognize from their existing bank details, so converting a domestic Danish account into IBAN form is largely a matter of concatenation rather than learning a new identifier. Anyone paying a Danish supplier, receiving a SEPA transfer, or filling in an international payment form that asks for an IBAN instead of separate registration and account numbers needs all 18 digits correct.

How this validator works

This tool checks the “DK” prefix, confirms the bank code block is 4 digits and the account number block is 10 digits, then runs the real mod-97 checksum (ISO 7064) Danish banks use to generate a valid IBAN — entirely client-side in your browser, no signup, nothing sent to a server. The result appears as soon as you stop typing.

What a pass doesn’t tell you

A pass confirms the IBAN is 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-digit bank code to an institution name and never contacts a bank, Danmarks Nationalbank, or any clearing system. If a Danish IBAN copied from a statement fails, the usual cause is a transposed digit in the 10-digit account block or a mismatched registration number — re-check both against the original source.

Scope: Danish IBAN structure and mod-97 checksum validation only — not payment processing, bank-code resolution, 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.