San Marino IBAN Format (SM) — Structure, Length & Example

The San Marino IBAN is 27 characters long and closely mirrors the Italian IBAN format, reflecting San Marino's geographic enclave within Italy and its deep integration with the Italian banking system. San Marino is a SEPA member and uses the euro under a monetary agreement with the EU. Payments to San Marinese accounts flow through the Italian interbank clearing network (BICR) and settle under the standard SEPA Credit Transfer timeline.

San Marino IBAN at a Glance

• Country code: SM
• Total length: 27 characters (always)
• Format: SMkk x bbbbb sssss cccccccccccc
• BBAN length: 23 characters
• Character types: 1-letter CIN check + 5-digit bank code (ABI) + 5-digit branch code (CAB) + 12-digit account number
• SEPA member: Yes

San Marino IBAN Structure Explained

1. Country Code — SM (2 characters)

The ISO 3166-1 alpha-2 code for the Republic of San Marino. Every San Marinese IBAN begins with SM.

2. Check Digits — kk (2 digits)

Two decimal digits calculated using the MOD-97 algorithm defined in ISO 7064. They guard against transcription errors and are verified by any IBAN-compliant validator.

3. CIN Check Character — x (1 uppercase letter)

A single uppercase letter derived from a modulo-26 computation over the bank code, branch code, and account number — inherited directly from the Italian BBAN format. Common values include letters from A to Z. The CIN provides an additional layer of domestic error detection on top of the IBAN check digits.

4. Bank Code (ABI) — bbbbb (5 digits)

The 5-digit Associazione Bancaria Italiana (ABI) code, which identifies the financial institution. Because San Marino uses the Italian ABI numbering system, you may see codes that also appear in Italian IBANs. Notable banks operating in San Marino:

• Cassa di Risparmio della Repubblica di San Marino (Carisp) — The largest domestic bank and historically the central savings institution of the republic.
• Banca di San Marino — A full-service commercial bank serving retail and corporate clients.
• Banca Agricola Commerciale (BAC) — Originally an agricultural credit institution, now a general commercial bank.
• Asset Banca — A smaller institution focused on private and wealth management clients.

5. Branch Code (CAB) — sssss (5 digits)

The 5-digit Codice di Avviamento Bancario (CAB), identifying the specific branch of the bank. The CAB structure is shared with Italian banks.

6. Account Number — cccccccccccc (12 digits)

A 12-digit numeric account identifier. Unlike the Italian BBAN where the account number is alphanumeric (c/o field), the San Marinese account field uses only decimal digits.

San Marino IBAN Example Explained

SM86 U032 2509 8000 0000 0270 100

This is an example IBAN for illustrative purposes only. Do not use for real transfers.

• Country: SM (San Marino)
• Check digits: 86
• CIN character: U
• ABI bank code: 03225
• CAB branch code: 09800
• Account number: 000000270100

Validate any San Marinese IBAN at the ibanchecker.cash IBAN validator, or view the complete format specification at /iban-format/sm.

How San Marino IBAN Validation Works

1. Country code check: The first two characters must be exactly SM.
2. Length check: The IBAN must be exactly 27 characters after removing spaces.
3. Character type check: Position 5 (CIN) must be an uppercase letter A–Z; positions 6–10 (ABI) and 11–15 (CAB) must be decimal digits; positions 16–27 must be decimal digits.
4. MOD-97 check: Move the first four characters to the end, substitute each letter for its numeric value (A=10 … Z=35), and divide by 97. A valid IBAN always yields a remainder of 1.

San Marino Is a SEPA Country

San Marino joined SEPA as part of its monetary agreement with the EU. This means:

• Euro transfers to San Marinese IBANs settle via SEPA Credit Transfer within one business day.
• SEPA Direct Debit mandates are supported for recurring euro payments.
• The IBAN alone is sufficient for SEPA transactions — no BIC code is required under the SEPA rulebook, though some institutions may still request it.
• San Marino is not an EU member state; it operates under a bilateral monetary and customs agreement.

Verify any San Marinese bank's BIC code using the ibanchecker.cash SWIFT directory.

San Marino vs. Italy: IBAN Similarities and Differences

Both IBANs are 27 characters and share the ABI/CAB/CIN structure. The primary differences are:

• Italian IBANs use country code IT; San Marinese IBANs use SM.
• The Italian account number field (c/o) is alphanumeric (12 characters, letters and digits); the San Marinese field is purely numeric.
• An Italian IBAN will not route to a San Marinese bank, even though the ABI codes may look similar.

Common San Marino IBAN Mistakes

Using IT Country Code Instead of SM

Because San Marino's banking infrastructure is deeply linked to Italy's, payers sometimes create an IBAN using IT instead of SM. This produces a structurally valid Italian IBAN that routes to an Italian bank, not San Marino — causing a misdirected payment.

Wrong Length — 26 or 28 Characters

San Marino IBANs are always 27 characters. A 24-character IBAN is not a valid San Marinese format. Count carefully after removing all spaces.

Mixing Up CIN with a Digit

The CIN character at position 5 of the BBAN is always an uppercase letter, never a digit. Entering a digit in that position produces an invalid IBAN that will be rejected by any compliant validator.

Validating San Marino IBANs in Bulk

Businesses trading with San Marinese suppliers or employers with cross-border payrolls can validate batches of IBANs using the ibanchecker.cash bulk checker. San Marinese IBANs can be mixed with Italian, French, or any other European country's IBANs in a single CSV upload.

Last updated: June 2026