Checksum Test Number Generator
Generates a fictional 13-digit number whose final digit is a correctly-computed mod-10 (Luhn) checksum — for testing checksum-validation code, never a real, assigned or usable number.
How to use this tool
- Press generate for a checksum-valid test number.
Common use cases
- Testing Luhn/mod-10 validation logic
- Teaching how checksum digits work
- Placeholder structured test data
Illustrative example data only — never a real, usable credential, address or in-use identifier.