BSB Lookup

A BSB has no check digit

Almost every identifier has arithmetic built into it: an ABN divides by 89, an IBAN by 97, a Medicare number carries a weighted check digit. A Bank State Branch number has none of that. Six digits, no relationship between them, no way to tell a real one from a made-up one by calculation alone.

What can be checked is allocation. Australian Payments Network Limited (AusPayNet) publishes the directory of every BSB in use, so the question a tool can actually answer is not "is this valid?" but "who does this belong to?". That is what this one does, and it will never call a well formed six digit number invalid, because there is no basis for the claim.

Bank, then branch

The first two or three digits identify the institution and the rest identify the branch. The institution half is answered from a few kilobytes bundled into this page, so it is instant and works with the network switched off. The branch half is 17,000 rows, which nobody should have to download to look up one number, so it is split into one small file per three digit prefix and fetched only when you ask about that prefix. Ask about a second BSB at the same bank and there is no second request.

A result gives the branch name, its suburb, state and postcode, and which clearing streams it accepts: direct entry is the ordinary electronic transfer, cheques is the paper stream, and high value is the RTGS one. Most branches take all three.

Merged branches still work

Branch networks shrink, and the directory records the closures rather than deleting them. A merged BSB keeps routing, because payments and direct debits set up against it years ago are still arriving, and the entry names the BSB that has taken it over. Chains happen: 012-003 points at 012-019, which points at 012-055. This tool follows the chain and shows you where it ends, which is usually the branch you actually wanted.

So an unfamiliar BSB on an old invoice is rarely wrong. It is more often a branch that closed, and the money would still get there.

The data ages, and says so

AusPayNet republishes the directory on the first business day of each month. Branches open, close and change hands between editions, so every result here is stamped with the date of the copy in use rather than presented as current fact. A BSB this tool does not recognise may simply be newer than the snapshot. That is also why nothing here is a substitute for confirming account details with the person you are paying: a BSB identifies a branch, never an account holder, and no lookup can tell you the money is going to the right person.

Storing and formatting BSBs

Store six digits as text so that a leading zero survives, and display them as three digits, a dash and three digits. Accept input with or without the dash, since both are common on statements and invoices. A BSB alone is not enough to send money: it needs an account number alongside it. For the New Zealand equivalent, see the New Zealand bank account validator; for Europe, the IBAN validator.

Where the data comes from

Source: Australian Payments Network Limited, "BSB Directory (Full Version)", as at 8 July 2026, and "Key to Abbreviations and BSB Numbers", as at 22 July 2026. Copyright © Australian Payments Network Limited. All rights reserved. Street addresses are not reproduced.

Every interpretation on this page, including the wording of each result and each warning, is ours alone. None of it should be attributed to AusPayNet, and none of it is a substitute for confirming account details with the receiving bank before you send money. AusPayNet publishes its own lookup, which is always the current edition.