Czech account number ↔ IBAN
Enter a Czech account number to get the IBAN — or the other way round. The tool validates the format and check digits and identifies the bank including its BIC (SWIFT) from the Czech National Bank list.
Input
Choose directionSpaces are fine. A Czech IBAN has 24 characters.
IBAN
—
- Prefix
- —
- Account number
- —
- Bank code
- —
- Bank
- —
- BIC (SWIFT)
- —
- Account number
- —
Bank codes per the Czech National Bank ČKPS list, version 254, valid from 1. 9. 2026.
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What a Czech account number looks like
The structure is set by Czech National Bank Decree No. 169/2011 Coll. on the rules for creating account numbers in payment transactions. An account number consists of an optional prefix (up to 6 digits), the base part (up to 10 digits) and a four-digit bank code assigned by the Czech National Bank. It is written as prefix-number/bank code, for example 19-2000145399/0800.
The modulo 11 check
Both numeric parts must pass a modulo 11 check. The digits are padded with leading zeros to their full length, each position is given a weight, and the sum of the products must be divisible by eleven:
- • Prefix (6 places) — weights left to right: 10, 5, 8, 4, 2, 1
- • Base part (10 places) — weights left to right: 6, 3, 7, 9, 10, 5, 8, 4, 2, 1
For the base part 2000145399: 2×6 + 0×3 + 0×7 + 0×9 + 1×10 + 4×5 + 5×8 + 3×4 + 9×2 + 9×1 = 121, and 121 is divisible by 11 — so the number is valid. This check catches most typos before the money goes to the wrong place.
How the IBAN is built
A Czech IBAN always has 24 characters in the structure CZkk BBBB PPPP PPCC CCCC CCCC:
- • CZ — country code per ISO 3166
- • kk — two check digits (MOD 97-10 algorithm, ISO 7064)
- • BBBB — four-digit bank code from the Czech National Bank list
- • PPPPPP — prefix padded with leading zeros to 6 places
- • CCCCCCCCCC — base part padded with leading zeros to 10 places
Account 19-2000145399/0800 therefore becomes CZ65 0800 0000 1920 0014 5399. The check digits are derived by moving the country code and two zeros to the end, replacing letters with numbers (A = 10 … Z = 35) and dividing by 97 — the check digits are 98 minus the remainder. When validating, the remainder after dividing by 97 must be 1.
Bank code and BIC (SWIFT)
Bank codes and their BICs come from the List of Payment Codes in the Czech Republic (ČKPS) published by the Czech National Bank — this tool uses version 254 (valid from 1. 9. 2026). Domestic payments use the four-digit bank code; international payments use the IBAN and, depending on the payment type, the BIC. For SEPA payments in euro within the EU the IBAN alone is usually sufficient.
Most common mistakes
- • A forgotten prefix — for accounts with a prefix it must sit at positions 9–14 of the IBAN, otherwise the payment fails.
- • Dropped leading zeros — the prefix and number are padded to full length inside the IBAN.
- • A mistyped digit — caught by the modulo 11 check or the IBAN check digits.
- • A non-existent bank code — the code must be in the Czech National Bank list.
Official sources
- • Decree No. 169/2011 Coll., on the rules for creating account numbers
- • Czech National Bank — accounts and bank codes (ČKPS list)
- • Czech National Bank — CERTIS payment system
This tool is for guidance and conversion. Always verify the beneficiary's account number with the counterparty — a valid format does not guarantee that the account exists or belongs to the intended recipient.
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P&T Europe accounting servicesFrequently asked questions
How is a Czech account number converted to an IBAN? +
A Czech IBAN has 24 characters in the form CZkk BBBB PPPP PPCC CCCC CCCC: the country code CZ, two check digits, a four-digit bank code, a six-digit prefix and a ten-digit account number. Both the prefix and the account number are padded with leading zeros. The check digits are computed with the MOD 97-10 algorithm (ISO 7064).
What is the modulo 11 check? +
Under Czech National Bank Decree No. 169/2011 Coll., both the prefix and the base part of an account number must pass a modulo 11 check. Each digit is assigned a weight (10, 5, 8, 4, 2, 1 for the prefix; 6, 3, 7, 9, 10, 5, 8, 4, 2, 1 for the base part, left to right) and the sum of the products must be divisible by eleven. This catches most typos.
Do I also need the BIC (SWIFT) for an international payment? +
For SEPA payments in euro within the EU the IBAN alone is usually enough — the beneficiary bank can be identified from the payment code contained in the IBAN via the Czech National Bank list. For non-SEPA payments or other currencies banks usually require the BIC. This tool shows the BIC where the Czech National Bank publishes one.
Why does the tool report an invalid account number? +
Most often it is a typo — the number fails the modulo 11 check. It can also be a bank code that is not in the Czech National Bank list, or a number outside the allowed range (prefix up to 6 digits, base part up to 10 digits). Also check that the prefix is separated by a hyphen and the bank code by a slash.
Is the account number sent anywhere? +
No. The conversion and all checks run entirely in your browser. Nothing is sent to a server or stored.
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