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Australia SWIFT/BIC code validator

How the SWIFT/BIC code format works

Format
8 or 11-character bank identifier code, country code AU in positions 5-6
Example
CTBAAU2S

Things to watch for

  • Structure: 4-letter bank code + AU (country) + 2-character location code, plus an optional 3-character branch code
  • An 8-character code (or one ending XXX) refers to the bank's head office, commonly in Sydney or Melbourne
  • No checksum digit — this is a format check only; it confirms positions 5-6 read AU, not that the bank or branch actually exists
Regex for SWIFT/BIC code
^[A-Z]{4}AU[A-Z0-9]{2}([A-Z0-9]{3})?$

An Australian SWIFT/BIC code identifies the bank on an international transfer, working alongside the BSB (Bank State Branch) number Australians use domestically. Every Australian BIC has AU fixed at positions 5-6, right after the 4-letter bank code, so a validator can confirm the country without a separate lookup. The country’s dominant “Big Four” banks split their SWIFT head offices between Australia’s two largest financial centres — Sydney and Melbourne — a rivalry that runs through Australian banking history.

Major Australian bank BIC prefixes

Bank BIC Location
Commonwealth Bank of Australia CTBAAU2S Sydney
National Australia Bank (NAB) NATAAU33 Melbourne
ANZ Bank ANZBAU3M Melbourne
Westpac WPACAU2S Sydney

How this validator works

This tool checks that the code is 8 or 11 characters, the first 4 characters are letters, positions 5-6 read AU, and the location and optional branch segments use only letters and digits — entirely client-side, with nothing sent to a server.

What a pass doesn’t tell you

A pass confirms the code is shaped like a real Australian BIC, not that CTBA, NATA, ANZB, or WPAC still names an operating bank, or that a location/branch suffix is current. There’s no checksum digit in a BIC, so a fabricated code that fits the pattern will still validate.

Scope: format validation only. Australian domestic transfers use the BSB and account number instead — the BIC mainly matters for incoming international SWIFT payments.

SWIFT/BIC code FAQ

What's the SWIFT code format for an Australian bank?

An Australian BIC is 8 or 11 characters: a 4-letter bank code, AU fixed at positions 5-6, a 2-character location code, and an optional 3-character branch code — for example CTBAAU2S for Commonwealth Bank's Sydney head office.

How do I read an Australian BIC?

In NATAAU33, NATA identifies National Australia Bank, AU is the country, and 33 is the Melbourne location code — a reminder that location codes in a BIC can be digits as well as letters.

Does an 8-character code work for an Australian bank?

Yes — the 8-character BIC and its 11-character equivalent ending XXX both point to the same head office and are accepted interchangeably.

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