Canadian · Validation
SEDOL check digit validator & calculator.
Verify a 7-character SEDOL's real check digit, or enter just the 6-character body to have the correct check digit computed for you. Everything runs in your browser: nothing you type is transmitted anywhere.
Inputs
Result
Enter a SEDOL and press Validate.
How the SEDOL check digit works
A SEDOL (Stock Exchange Daily Official List number) is 7 characters: a 6-character alphanumeric body and 1 numeric check digit, used to identify securities listed in the UK and Ireland. Each body character is converted to a value — digits keep their value, and letters are worth 9 plus their position in the alphabet (B = 11 through Z = 35). The vowels A, E, I, O and U are never used in a SEDOL at all, so a code can never be mistaken for a word. Those 6 values are multiplied by the fixed weights 1, 3, 1, 7, 3, 9 in order and summed. The check digit is whatever value would make that weighted sum a multiple of 10: (10 − (sum mod 10)) mod 10.
This is a different checksum from both ISIN and CUSIP: it is a straight weighted sum with no doubling step at all. Worked by hand against BAE Systems' real SEDOL, 0263494: body "026349" gives values (0, 2, 6, 3, 4, 9), weighted products (0, 6, 6, 21, 12, 81), a sum of 126, and check digit (10 − 6) mod 10 = 4 — matching the real, publicly known SEDOL.
What a passing checksum does and doesn’t tell you
A valid check digit only proves the characters are internally consistent — it does not confirm the SEDOL was ever actually assigned to a real security, or identify what that security is. SEDOLs are assigned and maintained by the London Stock Exchange; look an actual SEDOL up through your broker or the LSE's own reference data. This tool runs entirely in your browser: nothing you type is transmitted, stored, or logged.