Check Digit Generator

How Check Digit Generator Works?

The Check Digit Generator calculates a check character from the payload. It places the result where the chosen scheme requires it. The same input box covers modulus, permutation and quasigroup schemes.

1. 1Paste the payload without its check character.
2. 2Select the scheme (Luhn, GS1, Verhoeff, Damm, ISO 7064, or a national rule).
3. 3Normalise the input: remove spaces and convert letters to upper case.
4. 4Compute the check character with the scheme's rule.
5. 5Insert the check character at the scheme's position (end, position 9 for a VIN, positions 3–4 for an IBAN).

Check Digit Generator Formula

The generator formula is Output = insert(payload, f_scheme(payload), position_scheme).

c = f_scheme(payload)
Output = payload[0:k] ‖ c ‖ payload[k:]   (k = scheme check position)

• f_scheme is the selected algorithm.
• k is the insert position (end of string for most schemes).

Luhn (Mod 10): 3 → 12345678903
GS1 Mod 10: 5 → 12345678905
Verhoeff: 2 → 12345678902
Damm: 6 → 12345678906

Check Digit Generator Conversion Table

The Check Digit Generator table shows the payload 1234567890 completed under 8 schemes.

What is Check Digit Generator?

A Check Digit Generator is a multi-scheme tool that appends a check character to any payload under the scheme the user selects. The generator saves switching between separate calculators.

The same payload produces different check characters under different schemes, so the scheme must match the identifier type.

What are the uses of Check Digit Generator?

There are 3 main uses of the Check Digit Generator, including new identifier creation, scheme selection, and quick lookups.

• New identifier creation: Teams append check digits to new IDs.
• Scheme selection: Architects compare outputs before picking a scheme.
• Quick lookups: Support staff complete a code during a call.