Free tool
Free GTIN checker for Shopify and Google Shopping
Google Merchant Center disapproves products with an invalid GTIN, and matches the rest to its catalog by it. Paste up to 500 UPC, EAN, ISBN-13 or GTIN codes: we check each one's length, check digit and range, show the correct check digit when it's wrong, and tell you the code type and where its GS1 prefix was issued.
How the check works
The same rules Merchant Center applies
A GTIN is the barcode number that identifies a product across sellers: 8 digits (EAN-8), 12 (UPC-A), 13 (EAN-13, which includes ISBN-13 for books) or 14 (ITF-14 for cartons). Merchants use it so marketplaces, Google Shopping and AI shopping agents can match their listing to the exact product. The last digit is a check digit computed from the others, so one mistyped digit makes the code fail.
Some valid-looking codes are still rejected: prefixes 02, 04 and 2x are reserved for in-store and variable-measure items, and 05, 98 and 99 for coupons. These pass the check digit test but aren't product identifiers. Google disapproves or limits products whose GTIN is invalid (Google's GTIN requirements).
In Shopify, the barcode goes in each variant's Barcode (ISBN, UPC, GTIN, etc.) field, under Products → the product → the variant. Use the GTIN the manufacturer assigned to the product. Don't make one up or reuse another product's: a number can pass this check and still belong to someone else.
If a product genuinely has no GTIN, such as a handmade or custom item, leave the barcode empty rather than entering a SKU, and follow Google's guidance for products without identifiers.
Validation isn't lookup. This tool checks the number's format, length, check digit and prefix range. It doesn't tell you which product a GTIN belongs to or whether it's registered with GS1. To see who a GTIN is registered to, use GS1's official Verified by GS1 lookup. The prefix region shows which GS1 member organisation issued the company prefix, not where the product was made.
The full Shopify catalog audit runs this check on every variant barcode in your flagship products, and flags barcodes that aren't published in structured data. See the check →
Step-by-step fix: Shopify Invalid GTIN: How to Fix Barcode Errors
What makes a GTIN valid for Google Merchant Center?
It has 8, 12, 13 or 14 digits, its last digit is the correct check digit for the rest, and its prefix isn't one of the restricted ranges: 02, 04 and 2x (in-store or variable-measure items) or coupon prefixes (05, 98, 99). Google disapproves items whose GTIN fails these checks.
Why did my UPC lose its leading zero?
Spreadsheets treat a barcode as a number and drop leading zeros, so a 12-digit UPC starting with 0 turns into 11 digits. Format the barcode column as text before pasting. The tool shows the code with the zero restored when that makes it valid.
What if my product has no GTIN?
Leave the barcode field empty, and in your feed set identifier_exists to no. Don't put your SKU in the barcode field: an invalid GTIN is worse than none, because Google disapproves the item instead of treating it as a custom product.
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