Every country with a modern banking system needs a way to tell one bank branch apart from every other one, so a payment actually lands where it’s supposed to. The US calls that a routing number. The UK calls it a sort code. Australia calls it a BSB. Canada splits the job into two separate numbers. They all solve the same problem, and none of them work outside the country that issued them.
That last part trips people up more than anything else here. A US routing number typed into a UK international transfer form does nothing useful, because the two countries’ payment systems don’t share a numbering scheme. If you’re sending or receiving money across a border, you need a different identifier entirely, which the IBAN explainer covers.
Worth knowing up front: a routing number by itself is public information, printed on every check your bank issues and searchable online. It’s your routing number paired with your account number that lets someone set up a payment, whether that’s an employer setting up direct deposit or a company setting up a recurring debit. That’s exactly why account protections like the Direct Debit Guarantee exist, and why glancing over your statement regularly matters more than treating either number as a secret worth hiding.
United States: the routing number (ABA number)
A US routing number is 9 digits. It’s also called an ABA number, after the American Bankers Association, which administers the system. The Federal Reserve uses these numbers to process Fedwire transfers, and every newer electronic payment method, ACH included, still relies on the same numbering system to identify the paying bank.
The 9 digits aren’t random. The first four identify the Federal Reserve routing symbol for that institution, the next four identify the specific bank, and the last digit is a check digit calculated from the other eight, which is how systems catch a mistyped number before a payment goes anywhere.
Here’s the part worth flagging specifically: some banks use a different routing number for wires than they do for direct deposit or ACH payments. Both numbers are real and valid, they just route through different systems. If a form asks for your routing number, check which kind of payment it’s for before copying whichever one you find first in your banking app.
United Kingdom: the sort code
A UK sort code is 6 digits, almost always written as three pairs, like 12-34-56. It routes payments through the Bacs, Faster Payments and cheque clearing systems, and it works alongside your account number the same way a routing number works alongside yours in the US.
Sort codes were originally built as a hierarchical address: a chunk of the number pointed at a clearing bank, another chunk at a region, and so on down to an individual branch. You don’t need to decode any of that to use one. You just need the right 6 digits from your own bank, which you’ll find printed on your card, your statement, or your banking app. It’s the same sort code whether the account behind it is a current account or an easy-access savings account; the number identifies the branch, not the product.
The sort code also matters for anything set up to move automatically, a standing order or a direct debit alike: both need a correct sort code and account number pair before either scheme will accept the instruction.
Australia: the BSB
BSB stands for Bank State Branch, and it’s also 6 digits. It identifies the specific bank and branch that holds an account, the same role a sort code plays in the UK, and it’s paired with your account number for every domestic transfer. The Australian Payments Network maintains the official BSB register and is the source that resolves a given 6-digit code back to a real bank and branch.
Canada: transit number and institution number
Canada splits the same job across two numbers instead of one. The institution number is 3 digits and identifies the bank itself, the same for every branch that bank has. The transit number is 5 digits and identifies the specific branch, or for an online-only bank, a single transit number that covers every customer since there’s no physical branch to distinguish. Payments Canada assigns both and keeps the official directory that maps them to real institutions.
Different forms ask for these two numbers in different orders and combinations depending on the payment type, so don’t assume a format you’ve seen once is universal. If a form specifies exactly how it wants the institution and transit numbers combined, follow that instruction rather than guessing from a template you found somewhere else.
Setting up direct deposit or payroll
This is the single most common reason someone goes looking for these numbers in the first place: a new employer, a benefits provider, or a government agency needs somewhere to send money. The request usually maps directly onto whichever number this article covers for your country:
- US employer: routing number plus account number, and confirmation of whether it’s a checking or savings account.
- UK employer: sort code plus account number, sometimes alongside your name exactly as it appears on the account, since some payroll systems cross-check it.
- Australian employer: BSB plus account number.
- Canadian employer: institution number and transit number, usually via a void cheque image or a direct-deposit form your bank can print on request.
The one habit worth building here: double-check the number against your own banking app or a recent statement immediately before submitting it, rather than trusting a number you memorised months ago. Banks occasionally reissue account numbers after a merger or a system migration, and a payroll department has no way of knowing yours changed unless you tell them.
| Country | What it is called | Length | What it identifies |
|---|---|---|---|
| United States | Routing number (ABA number) | 9 digits | Bank, plus Federal Reserve district |
| United Kingdom | Sort code | 6 digits | Bank and branch |
| Australia | BSB (Bank State Branch) | 6 digits | Bank and branch |
| Canada | Institution number + transit number | 3 digits + 5 digits | Bank, then branch, separately |
Domestic transfers vs international transfers
Here’s the distinction that actually matters day to day: routing numbers, sort codes, BSBs and transit numbers only work for domestic payments, inside the payment rails their own country built for them. A US bank moving money to another US bank uses a routing number. A UK bank moving money to another UK bank uses a sort code. Neither one means anything to a bank in a different country.
For a payment that crosses a border, banks fall back to a different identifier: a SWIFT/BIC code for the receiving bank, and in many countries outside the US and Canada, an IBAN for the account itself. If you’ve been asked for one of those and assumed it was just another name for your routing number or sort code, it isn’t. The IBAN guide walks through what that number actually is and which countries expect one.
The most common mistake: using the wrong number for the wrong payment
The single biggest source of failed or delayed transfers isn’t a mistyped digit, it’s using the right kind of number for the wrong purpose. A wire routing number sent where an ACH routing number was expected can bounce, get delayed, or in some cases still process but through the wrong internal path at the bank. The same logic applies in every country here: a sort code that’s correct but entered into a field expecting an IBAN will simply fail validation.
Before sending or receiving a meaningful amount, it’s worth confirming three things: which country’s system the payment is moving through, which specific number that system needs, and whether your own bank uses more than one number depending on payment type. That third one catches more people than the first two combined, mostly because most people only ever check their number once, when they first need it, and never again.
Where to actually find your number
All four countries make this easier than it sounds. Your number, whichever kind it is, shows up in the same handful of places:
- Printed on a physical check, if your account issues them. In the US this sits at the bottom left, in front of the account number.
- On your account summary or statement, either the paper version or inside your banking app.
- In your online or mobile banking app, usually under account details or account settings.
- On a recent direct deposit form, if your employer or another payer has ever asked you for your details before.
If none of those are handy, calling your bank directly is faster than searching for it, and it avoids the risk of copying a number from a third-party lookup site that’s out of date. Third-party routing-number and BSB lookup tools exist and are mostly accurate, but the number that matters is the one your own bank confirms, not the one a search result guesses.
One more thing worth checking while you’re at it: how your account is actually structured. If you’re weighing a high-yield savings account against where your current account sits, or comparing savings rates across the US, UK, Canada and Australia, the routing details are the same regardless of which product you choose. They identify the branch, not the account type, so switching to a better-paying account at the same bank won’t change any of the numbers covered here.
Once money actually lands, reading the statement itself is the next piece worth understanding, especially the gap between what shows as pending and what’s actually settled.