Slovenia IBAN validator
How the IBAN format works
- Format
- SI + 2 check digits + 15-digit bank/branch/account number (19 chars)
- Example
- SI56263300012039086
Things to watch for
- 19 characters total, all numeric
^SI[0-9]{2}[0-9]{15}$A Slovenian IBAN is 19 characters: “SI”, two check digits, a 5-digit combined bank/branch code, an 8-digit account number, and 2 national check digits — 15 digits in that domestic block, all numeric. Those final 2 digits are a holdover from Slovenia’s own pre-IBAN account-numbering formula, layered underneath the mod-97 checksum the IBAN carries near the start, so a Slovenian account number effectively has two independent layers of built-in error detection. Anyone paying a Slovenian supplier, invoicing a client based in Slovenia, or filling in a SEPA transfer form needs all 15 digits of that block correct, including the national check digits that are easy to mistake for extra account-number padding.
How this validator works
This tool checks the “SI” prefix, confirms the bank/branch block is 5 digits, the account-number block is 8 digits, and the national check-digit block is 2 digits, then runs the real mod-97 checksum (ISO 7064) Slovenian banks use to generate a valid IBAN — entirely in your browser, nothing sent to a server, no signup required.
What a pass doesn’t tell you
A pass confirms the 19 characters are correctly formed and internally consistent — not that the account is open, active, or belongs to whoever you expect. This tool doesn’t resolve the bank/branch code to an institution name and never contacts a bank or the Bank of Slovenia. If a Slovenian IBAN fails, check first whether the trailing 2 national check digits got merged into or dropped from the 8-digit account-number block — that boundary, with no visual separator in the raw IBAN, is the detail most often mistyped.
Scope: Slovenian 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 blocks inside a Slovenian IBAN's 15-digit domestic number?
A 5-digit combined bank/branch code, an 8-digit account number, and 2 national check digits at the end — 15 digits total after 'SI' and the IBAN's own 2 check digits, for 19 characters overall.
How do those trailing national check digits differ from the IBAN's mod-97 checksum?
They're a separate, older domestic check value computed over the bank/branch code and account number under Slovenia's pre-IBAN numbering scheme, distinct from the mod-97 (ISO 7064) checksum that validates the IBAN as a whole from the two check digits near the start.
Does this tool verify those national check digits separately?
No. It validates the full 19 characters using the IBAN-level mod-97 checksum only, without isolating and recomputing the domestic national check-digit formula as its own step — and it doesn't confirm the account is open or belongs to anyone.