What is a Sort Code?

A sort code is a 6-digit numerical code used by banks and financial institutions in the United Kingdom and the Republic of Ireland to identify specific bank branches. The code is written in the format XX-XX-XX (for example, 20-00-00 for a Barclays branch).

Sort codes were introduced to automate and standardise the routing of domestic payments through the inter-bank clearing systems. Every bank branch in the UK and Ireland that participates in the payment network is assigned a unique sort code.

Sort Code Structure

A sort code consists of 6 digits divided into three pairs:

• Digits 1–2 (Bank Identifier): Identify the bank or financial institution. For example, 20 is assigned to Barclays, 30 to Lloyds, and 40 to HSBC.
• Digits 3–4 (Regional / Head Office Identifier): Indicate the geographic region or divisional grouping within the bank.
• Digits 5–6 (Branch Identifier): Identify the specific branch within that region.

Together the six digits create a unique identifier for a single branch in the UK or Irish banking network.

What are Sort Codes Used For?

Sort codes are required for many types of domestic payments and banking operations in the UK and Ireland:

• Domestic bank transfers (BACS / Faster Payments): Used alongside an account number to route money between accounts.
• Direct Debits and Standing Orders: The sort code and account number together identify the account to be debited or credited on a recurring basis.
• Cheque processing: Printed on all UK cheques in MICR format so that cheques can be automatically sorted and processed through the clearing system.
• CHAPS payments: Same-day high-value bank transfers also rely on sort codes for routing within the UK.
• Payroll and salary payments: Employers use the sort code and account number to deposit wages via BACS.
• Setting up bank accounts: Required when giving payment details to an employer, government body, or business.

Where to Find Your Sort Code

• Debit card: Printed on the front or back of your card under account details.
• Bank statements: Displayed at the top of paper and digital statements.
• Online / mobile banking: Found in the account details or payment settings section.
• Chequebook: Printed at the bottom of each cheque in the MICR line — the first 6-digit number on the bottom-left.
• Welcome letter: Sent by your bank when you opened your account.

Sort Code vs. Account Number

These two numbers work together but serve different purposes:

• Sort code (6 digits): Identifies the bank and the specific branch.
• Account number (8 digits): Identifies your individual account at that branch.

For any UK domestic payment, both are required. Providing only one will result in a failed or misdirected payment.

Sort Code vs. IBAN vs. SWIFT Code

For international payments, sort codes alone are not sufficient. Here is how they relate to other codes:

• IBAN (International Bank Account Number): The UK IBAN combines the sort code and account number into a standardised 22-character format — e.g., GB29 NWBK 6016 1331 9268 19. Required for SEPA and international wire transfers.
• SWIFT / BIC code: Identifies the bank globally, not the branch. Required alongside an IBAN for most international wire transfers.
• Sort codes are UK/Ireland-only: They carry no meaning outside these two countries and cannot be used to route international payments.

Common Mistakes and Things to Be Careful Of

• Transposing digits: Entering 20-30-40 instead of 20-40-30 routes the payment to the wrong branch entirely. Always copy the exact sequence character by character.
• Using a sort code alone: A sort code without the matching account number cannot identify where to send money. Always provide both together.
• Old or retired sort codes: Banks sometimes merge branches and retire sort codes. An obsolete sort code may still appear on old documents but can cause payment failures. Verify the code is still active before sending a payment.
• Sort codes are not a security secret: Your sort code is printed on cheques and statements and is not confidential. However, combined with your account number it can be used to set up a fraudulent direct debit — guard your full account details carefully.
• International transfers: Never use a sort code for an international transfer. Use your IBAN and your bank's SWIFT / BIC code instead.
• Formatting variations: Sort codes may be written as 20-00-00, 200000, or 20 00 00 depending on the system. All formats represent the same underlying code — formatting does not affect the value.

Sort Codes in Other Countries

Sort codes are specific to the UK and Ireland. Equivalent systems in other countries include:

• Germany: BLZ (Bankleitzahl) — 8-digit bank routing code.
• United States: ABA Routing Transit Number (RTN) — 9-digit code.
• Australia: BSB (Bank State Branch) — 6-digit code, conceptually similar to a sort code.
• India: IFSC (Indian Financial System Code) — 11-character alphanumeric code.
• International: SWIFT / BIC codes are used worldwide for interbank identification across borders.