Sweden formats its IBAN in 24 characters with the BBAN pattern ^[0-9]{20}$: an all-numeric domestic number split into a 3-digit bank identifier and a 17-digit account number.
Breakdown
The official registry example is SE45 5000 0000 0583 9825 7466, a SWIFT registry test value rather than a real account:
SE45- country code and IBAN check digits500- the 3-digit IBAN ID identifying the bank, here SEB (Skandinaviska Enskilda Banken)00000058398257466- the 17-digit account number
The clearing-number and IBAN-ID system
Domestic Swedish payments are addressed by a clearing number - four digits for most banks, five for a few such as Swedbank - that identifies the bank and branch, followed by an account number. The IBAN does not embed the clearing number. Instead Bankinfrastruktur (BSAB), the banks’ shared payment-infrastructure body, assigns each institution a 3-digit IBAN ID and publishes the table that maps clearing-number ranges to it; the conversion places that ID in the first three BBAN digits.
A single bank holds one IBAN ID but usually many contiguous clearing ranges - Nordea’s ID 300 spans nine ranges and SEB’s 500 three - so the sixty-odd clearing-range rows in the official table collapse to roughly four dozen banks. There is no branch field inside the IBAN, and the Swedish BBAN carries no national check digit that an IBAN validator tests, so structural integrity rests on the IBAN’s MOD-97 check digits alone.
Currency and SEPA context
Sweden is an EU member but keeps the Swedish krona rather than the euro; it participates fully in the SEPA schemes, so euro transfers to and from SE IBANs use standard SEPA rails while domestic traffic settles in kronor over the local system.
Validity remains structural only. A 24-character string that passes the checksum may reference a closed account or an unissued IBAN ID, and it says nothing about the holder’s identity. Name-matching services in the style of the EU’s Verification of Payee are the safeguard against paying a well-formed number that belongs to the wrong person.