IBAN vs. bank account number: when to use IBAN and when local format is enough

A Czech bank account number and an IBAN are not the same thing. For domestic transfers, a regular account number and bank code are usually enough. Once a payment crosses borders or is processed by an international banking system, IBAN is usually required.

What is a local bank account number

In the Czech Republic an account is commonly written like 123456789/0100. This format works for domestic transfers between Czech banks.

What is IBAN

IBAN is the international bank account format. A Czech IBAN starts with CZ and also contains check digits. This reduces transfer errors and makes international payments easier to process.

When you need IBAN

• when sending or receiving international payments,
• when invoicing a foreign client,
• when using global payment gateways or accounting systems.

When a local account number is enough

For standard domestic Czech bank transfers, IBAN is usually not necessary. A local account number, bank code and variable symbol are typically enough.

The most common mistake

Many people manually rewrite an account number into something they think is IBAN. That creates unnecessary risk. It is better to generate and validate IBAN automatically.

If you issue invoices to clients outside the Czech Republic, including IBAN is the safer default and helps avoid failed transfers.