Tools › GTIN validator
Free GTIN / UPC / EAN Barcode Validator
Paste your barcodes — one per line — and check each one instantly. This tool runs the real GS1 mod-10 check-digit math (the same check Google Merchant Center runs), flags the wrong length or a bad checksum, and tells you what's wrong. Everything happens in your browser; nothing is uploaded.
Checking your catalog by hand?
Feed Doctor scans every product in your Shopify catalog automatically — GTINs, titles, images, descriptions, prices and the other fields Google rejects — before you push the feed.
Try Feed Doctor free for 7 days →What makes a GTIN invalid
- Wrong length — a GTIN is 8, 12, 13, or 14 digits. An 11-digit value is usually a UPC missing its leading zero.
- Not digits — spaces, dashes, letters, or a trailing
.0from a spreadsheet make it invalid. - Bad check digit — the last digit is a checksum; one mistyped or transposed digit breaks it. A made-up barcode almost always fails here.
For the full fix on Shopify, see how to fix an invalid GTIN and the missing-GTIN error.
Frequently asked questions
What counts as a valid GTIN?
A GTIN is 8, 12, 13, or 14 digits (EAN-8, UPC-A, EAN-13, GTIN-14), digits only, and its last digit must match the GS1 mod-10 checksum computed from the others. This tool checks all three.
Why is my 11-digit barcode invalid?
Valid GTIN lengths are 8, 12, 13, and 14. An 11-digit value is almost always a 12-digit UPC that lost its leading zero in a spreadsheet — add the zero back.
Is my SKU a GTIN?
No. A SKU is your internal stock code and is not a valid GTIN. Google reads the manufacturer barcode (UPC/EAN) from Shopify’s Barcode field, not the SKU.
Do you upload or store my barcodes?
No. This tool runs entirely in your browser — the barcodes you paste never leave your device and are never sent to a server.
How do I fix an invalid GTIN on Shopify?
Enter the correct, complete barcode in each variant’s Barcode field, or mark genuinely custom products as having no GTIN. Our guide walks through it step by step.