GTIN Mod-10 Validator
Paste GTINs, get pass/fail with the failing checksum digit
Validates GTIN-8, GTIN-12, GTIN-13, and GTIN-14 codes against the Mod-10 checksum that Google Merchant Center applies before accepting them. Catches bad GTINs before they kill your Shopping feed instead of after.
- Paste GTINs in the input box, one per line. GTIN-8/12/13/14 are all supported.
- The validator zero-pads to 14 digits, then runs the standard Mod-10 algorithm: sum every other digit ×3, sum the rest ×1, the check digit is whatever makes the total a multiple of 10.
- Each GTIN comes back as Pass, Fail with expected check digit, or Invalid (wrong length, non-numeric, etc.).
- Copy the failing GTINs in one click for re-keying.
Per-line results
Paste GTINs to validate.
Why this exists
A single bad GTIN can disqualify an entire Shopping listing, and Merchant Center will not tell you which one until 24 hours after upload. Catching this in 5 seconds before a feed push has saved real campaigns.
Frequently asked
What is the GTIN Mod-10 algorithm?
Mod-10 is the checksum algorithm used for GTIN-8, GTIN-12 (UPC), GTIN-13, and GTIN-14 product codes. The 14-digit padded form sums every other digit ×3 plus the rest ×1; the check digit is whatever makes the total a multiple of 10. Google Merchant Center and every major retailer validate against this checksum on upload.
Why does Google Merchant Center reject my GTINs?
The most common reasons are: (1) failed Mod-10 checksum from a single transposed digit, (2) wrong length (e.g. 9 digits instead of 12), (3) non-numeric characters, (4) the GTIN belongs to a different brand than your account claims. This validator catches the first three before upload.
Does this work for ISBN-13 codes?
Yes. ISBN-13 uses the same Mod-10 checksum as GTIN-13. Paste an ISBN-13 (with or without dashes) and the validator will confirm the check digit.