Czech Republic IBAN Format (CZ) — Structure, Length & Validator

The Czech Republic IBAN format is used for all electronic bank transfers to Czech accounts within SEPA and internationally. The Czech IBAN preserves the country's unique domestic account number structure — including an optional account prefix — making it one of the longer Central European IBAN formats at 24 characters.

Czech IBAN at a Glance

• Country code: CZ
• Total length: 24 characters (always)
• Format: CZkk bbbb ssssss cccccccccc
• BBAN length: 20 digits
• Currency: Czech koruna (CZK)
• SEPA member: Yes (not eurozone)

Czech IBAN Structure Explained

A Czech IBAN contains five components within its 24-character structure:

1. Country Code — CZ (2 characters)

The ISO 3166-1 alpha-2 code for the Czech Republic. Every Czech IBAN begins with CZ and this never varies.

2. Check Digits — kk (2 digits)

Two decimal digits calculated with the MOD-97 algorithm. They protect against transcription errors and are fixed for the lifetime of the account.

3. Bank Code — bbbb (4 digits)

A 4-digit code identifying the bank, assigned by the Czech National Bank (ČNB). Common bank codes:

• 0800 — Česká spořitelna
• 0300 — ČSOB (Československá obchodní banka)
• 0100 — Komerční banka
• 2010 — Fio banka
• 5500 — Raiffeisenbank Czech Republic

4. Account Prefix — ssssss (6 digits)

An optional 6-digit prefix that in the Czech domestic system separates special account types (e.g., savings accounts or company sub-accounts). If no prefix is used, this field is zero-padded: 000000. Many Czech bank statements show this as a separate field before a hyphen in the account number.

5. Account Number — cccccccccc (10 digits)

The 10-digit base account number. Czech account numbers were historically shorter and are left-padded with zeros to reach exactly 10 digits in the IBAN.

Real Czech IBAN Example

CZ65 0800 0000 1920 0014 5399

• Country: CZ
• Check digits: 65
• Bank code: 0800 (Česká spořitelna)
• Account prefix: 000019
• Account number: 2000145399

Electronic format: CZ6508000000192000145399

How Czech IBAN Validation Works

1. Country code: First two characters must be CZ.
2. Length: Exactly 24 characters after spaces are removed.
3. Character types: Positions 3–24 must all be decimal digits. Czech IBANs contain no letters after the country code.
4. MOD-97: Rearrange the first four characters to the end, convert letters to numbers, and compute modulo 97. The result must equal 1.

The ibanchecker.cash validator performs all four checks automatically. Paste any Czech IBAN to see the bank name, BIC, and a full breakdown of prefix and account number.

Czech Republic and SEPA

The Czech Republic is a SEPA member but not a eurozone country — it retains the Czech koruna (CZK). This means Czech accounts can receive SEPA Credit Transfers and participate in SEPA Direct Debits, but currency conversion applies when sending euros to a Czech account (or CZK to a eurozone account). For international transfers outside the SEPA zone, the bank's BIC/SWIFT code is required. Find any Czech bank's BIC with the ibanchecker.cash SWIFT directory.

Common Czech IBAN Mistakes

Forgetting the Account Prefix Field

Czech domestic account numbers are often written as 000019-2000145399/0800. The prefix (000019) and account number (2000145399) are separate fields in the IBAN. Omitting the prefix field entirely produces a 18-character BBAN (missing 6 digits) and an invalid IBAN.

Using the Slash-Separated Domestic Format

Czech domestic account numbers are traditionally written with a slash separating the account number from the bank code (2000145399/0800). This format cannot be used for SEPA or international transfers — the full 24-character IBAN is required.

Validating Czech IBANs in Bulk

Finance teams processing payments to Czech suppliers can validate multiple IBANs at once with the ibanchecker.cash bulk checker. Upload a CSV with up to 100 IBANs and get instant validation results, bank names, and BIC codes per row.

Last updated: June 2026