IBAN

What is IBAN?

IBAN (International Bank Account Number) is the international standardised format for bank account numbers defined by the ISO 13616 standard. It was created in 1997 by the European Commission and ECBS (European Committee for Banking Standards) to harmonise cross-border payments. The length of an IBAN varies by country (from 15 to 34 characters) — a Slovak IBAN has 24 characters.

Structure of a Slovak IBAN, e.g. SK31 1200 0000 1987 4263 7541:

• SK — ISO country code (Slovakia)
• 31 — two-digit check digit (MOD 97-10)
• 1200 — bank code (e.g. 1200 = Tatra banka)
• 0000 — account prefix
• 1987 4263 7541 — account number

The check digit allows automatic validation of whether an IBAN is syntactically correct — if an accounting system rejects an entered number, it is a typo or an incorrect number.

When it is used

IBAN is mandatory for:

• All cross-border SEPA transfers in EUR
• Most domestic transfers (de facto universal in Slovakia and across the EU)
• Issuing invoices — including the IBAN on an invoice is good practice and expected by trading partners

See the Invoicing module and the Accounting module.

Related terms

• SEPA — the payment scheme based on IBAN. See /en/glossary/sepa.
• QR platba — the QR payment code contains the payee’s IBAN. See /en/glossary/qr-platba.
• e-Invoice — IBAN is a mandatory field in EN 16931. See /en/glossary/e-invoice.

In Modulario

Modulario validates IBAN when creating both customer and supplier records — checking both the check digit and format. Invoicing automatically inserts the IBAN into issued invoices and generates a QR payment code with the payee’s IBAN. In Accounting the system matches incoming payments to receivables by IBAN and variable symbol.

Modulario validates supplier IBANs against EU sanctions lists — automatic protection against paying a sanctioned entity. For international payments outside the EU/SEPA zone, you also need the SWIFT/BIC code of the bank in addition to the IBAN (e.g. TATRSKBX for Tatra banka). Within the SEPA zone, a BIC is not required since 1 February 2014 thanks to the “IBAN-only” rule.