How does an IBAN map to a BIC?

Each country's IBAN reserves a fixed slice of characters for the bank code. The tool extracts that slice based on the country code, then looks the bank code up in a bundled registry to return the bank's primary BIC. No single global formula exists, so the mapping is per-country.

Why might the BIC not be found?

The bundled registry covers major banks across 40+ countries but not every minor or regional institution. If your bank code is not listed, the tool still confirms the IBAN is structurally valid and tells you the extracted bank code so you can check the official SWIFT directory.

Is the returned BIC the branch BIC?

It is the bank's primary or head-office BIC (the 8-character form). Some banks use branch-specific BICs in positions 9 to 11. For payment-critical transfers, confirm the exact BIC with the beneficiary's bank.

Does this call an external API?

No. The lookup uses a registry bundled into the page, so it works offline and sends nothing to any server. Your IBAN never leaves your browser.

Does a found BIC mean the account is valid?

It means the IBAN passed the MOD-97 checksum and the bank code matched a known bank. It does not confirm the account number itself is open or owned by anyone in particular.

IBAN to BIC Lookup Tool

A BIC (Bank Identifier Code, also called a SWIFT code) tells an international payment which bank should receive the money, while the IBAN identifies the specific account. Many cross-border transfers need both, but if you only have the IBAN you can usually recover the BIC, because every IBAN embeds the bank code in a fixed position. This tool extracts that code and resolves the BIC from a bundled multi-country registry, entirely in your browser with no API call.

Paste any IBAN and the tool validates the checksum, pulls out the bank code, and returns the matching BIC and bank name when it knows them.

How it works

There is no single global rule mapping IBAN to BIC, because each country places its bank code at a different position and uses a different format. The tool handles this in three steps:

Validate the checksum — the IBAN is rearranged (first four characters to the end), letters are expanded to numbers (A=10 through Z=35), and the result is divided by 97. A remainder of 1 means the structure is trustworthy.
Extract the bank code — using the country code, the tool slices the exact characters reserved for the bank identifier. For example, a UK IBAN uses 4 letters at positions 5 to 8, while a German IBAN uses 8 digits.
Look up the BIC — the extracted bank code is matched against a bundled registry of major banks across 40+ countries, returning the bank name and its primary BIC.

If the checksum fails, the tool still attempts extraction but warns you that the bank code may be unreliable.

Tips, example, and limits

For the IBAN GB29 NWBK 6016 1331 9268 19, the country code is GB, the bank code slice is NWBK, and the registry returns NatWest Bank with BIC NWBKGB2L.

IBAN:      GB29 NWBK 6016 1331 9268 19
Country:   GB
Bank code: NWBK
BIC:       NWBKGB2L  (NatWest Bank)

The registry is curated for breadth across countries rather than total coverage within each one, so smaller banks may return “not in registry” even when the IBAN is perfectly valid. In that case the tool shows you the extracted bank code so you can confirm the BIC against the official SWIFT directory. Always verify the exact BIC with the beneficiary’s bank for payment-critical transfers. Everything runs locally and nothing is uploaded.