What is a UK sort code?

A sort code is a 6-digit number that identifies the bank and branch a UK account belongs to. It is usually written in three pairs, for example 12-34-56.

Can a sort code be fully validated offline?

The format (6 digits) can be checked offline, and the bank can be inferred from the leading-digit ranges. Confirming the exact branch or that an account exists requires the bank's own modulus-check data and APIs.

What does the bank lookup use?

It uses the well-known leading-two-digit ranges that UK clearing banks are assigned (for example 04 for Monzo, 20-29 for Barclays, 40-49 for HSBC). It is a best-effort match, not a full branch directory.

Does a valid format mean the account is real?

No. A valid 6-digit format means the sort code is structurally correct, not that a specific account or branch exists. Always confirm payment details with the payee.

Is my sort code sent anywhere?

No. All checks run locally in your browser. The sort code never leaves your device.

UK Sort Code Validator

A UK sort code is the 6-digit number that identifies which bank and branch a current or savings account belongs to. It appears on cards, cheques and bank statements, usually grouped as three pairs like 12-34-56. This free validator checks that a sort code is structurally correct and tells you which bank the leading digits point to — useful when pre-validating payment forms or de-duplicating supplier records.

How it works

A sort code is exactly 6 digits, conventionally written as three pairs separated by dashes. The validation here has two parts:

Format check — strip any spaces and dashes, then confirm exactly 6 numeric digits remain.
Bank identification — the first two digits map to a clearing bank using publicly documented ranges. For example 04 is Monzo, 20–29 is Barclays, 30–39 is Lloyds, 40–49 is HSBC, 60–62 is NatWest, and 09/07 are Santander legacy ranges.

The leading-digit map is best-effort: it identifies the bank, not the specific branch. The authoritative branch directory and the per-account modulus check require Vocalink’s EISCD/modulus data.

Example

Validate 12-34-56 → normalised digits 123456. The format is valid (6 digits). The leading pair 12 falls in the Clydesdale/Yorkshire Bank range, so the tool reports that bank.

Tips and notes

Because the bank ranges overlap with newer challenger banks and re-assignments happen, treat the bank name as a strong hint rather than a guarantee. For payment-critical flows you should still run the official modulus check before debiting an account. Everything in this tool runs locally — your data never leaves the browser.