A sort code is the 6-digit UK bank identifier (format 12-34-56). A routing number is the 9-digit US equivalent (also called an ABA routing number or RTN). They do the same job — identifying the bank that holds an account — but they are not interchangeable. UK banks do not have routing numbers, and US banks do not have sort codes. For any transfer between the UK and the US, you will also need a SWIFT/BIC code and usually an IBAN.
This guide explains how sort codes, routing numbers, and account numbers work, how to find them, how many digits each one has, and exactly what you need when sending money internationally. For international transfer mechanics, see our SWIFT transfers guide, and for paying a USD invoice from the UK, see our GBP to USD transfer guide.
Sort Code vs Routing Number: Are They the Same?
No. A sort code and a routing number are not the same, although they serve the same purpose in different countries.
| Feature | UK Sort Code | US Routing Number |
|---|---|---|
| Country | United Kingdom | United States |
| Length | 6 digits | 9 digits |
| Format | 12-34-56 |
123456789 |
| Identifies | Bank and branch | Bank (and sometimes region) |
| Also known as | Sorting code | ABA number, RTN, transit number |
| Used with | 8-digit account number | 8–12 digit account number |
What Is a Sort Code?
A sort code is a 6-digit number that identifies a specific UK bank and branch. It is written in three pairs separated by dashes, for example 20-00-00 (Barclays) or 40-00-00 (HSBC). You need a sort code for: Faster Payments and BACS transfers within the UK, direct debits and standing orders, receiving salary, and giving bank details to employers, HMRC, or clients. Find yours in your mobile banking app, online banking account summary, or on your debit card.
What Is a Routing Number (US)?
A routing number is a 9-digit code that identifies a US bank for domestic payments. Also called an ABA routing number or routing transit number (RTN). A single US bank can have multiple routing numbers depending on the state the account was opened in. You need a routing number for: direct deposit with a US employer, ACH transfers, domestic wire transfers, and receiving tax refunds.
How Many Digits Is Each Number? Quick Reference
| Identifier | Country | Digits |
|---|---|---|
| Sort code | UK | 6 |
| Account number | UK | 8 |
| Routing number (ABA) | US | 9 |
| Account number | US | 8–12 (varies) |
| IBAN (UK) | UK | 22 characters |
| SWIFT / BIC | Global | 8 or 11 characters |
International Transfers: What You Actually Need
Sort codes and routing numbers are domestic identifiers. They do not work across borders on their own. For international transfers:
Sending money into a UK account (from abroad): IBAN (22 characters starting with GB), SWIFT/BIC code, and recipient name and address.
Sending money into a US account (from abroad): SWIFT/BIC code of the US bank, ABA routing number (the international wire routing number), account number, and recipient name and full US address. The US does not use IBANs.
For a full breakdown, see our guide to IBANs, SWIFT codes and routing numbers.
Common Transfer Scenarios Using These Details
Getting these identifiers right is the first step — but the exchange rate is where the real cost is. See our relevant guides: paying USD invoices from the UK (ABA routing number required), paying euro bills from the UK (IBAN and SWIFT/BIC required), best way to transfer pounds to euros, bank wire transfer fees explained, and how long international bank transfers take. For large transfers, see transferring large sums internationally and how much you can send abroad from the UK.
Is It Safe to Share Your Sort Code and Account Number?
Yes — in the UK, sharing your sort code and account number is safe for receiving payments. They are designed to accept money, not extract it. No one can withdraw funds using only these two numbers. Never share card numbers, expiry dates, CVVs, online banking passwords, or one-time passcodes.
Moving Money Internationally? Skip the Bank Markup
Getting the numbers right is only half the job. The other half is the exchange rate. High-street banks typically add a 3–4% margin to the interbank rate on international transfers. See why banks give worse exchange rates, what international transfers actually cost, and who gives the best exchange rates for large transfers. All Cambridge Currencies transfers are processed through FCA-authorised payment partners and are fully safeguarded.
Request a live quote or speak to a specialist about your transfer.
