Fix Luhn checksum fail
Luhn (mod-10) checksum validates card numbers, IMEI, etc. Wrong check digit causes validation failure.
Common causes
- Check digit computed wrong.
- Digits reversed or truncated.
- Non-numeric characters.
How to fix
- Recalculate check digit with Luhn algorithm.
- Use Checksum Validator to verify.
- Ensure input is digits only.
Use our tool
Validate checksum