GTIN Validator

What is a GTIN?

A GTIN (Global Trade Item Number) is a unique identifier assigned to products for use in commerce. It's the number encoded in barcodes you see on every product. GTINs are managed by GS1 and come in several formats:

• GTIN-8 (EAN-8) — 8 digits, used for small products with limited packaging space
• GTIN-12 (UPC-A) — 12 digits, primarily used in North America
• GTIN-13 (EAN-13) — 13 digits, the most widely used format worldwide
• GTIN-14 — 14 digits, used for trade items at various packaging levels

How does GTIN validation work?

Every GTIN includes a check digit — the last digit — calculated from all preceding digits using a standard algorithm. This tool verifies that the check digit is correct, identifies the GTIN format, and looks up the GS1 country prefix to show where the barcode was registered.

Valid GTINs are essential for product listings on marketplaces like Amazon, Google Shopping, and eBay. Incorrect GTINs can lead to listing rejections and poor catalog data quality. Read why GTIN errors are the cheapest catalog problem to fix.

How is the GTIN check digit calculated?

All GTIN formats use the same mod-10 algorithm. Take every digit except the last one, then:

1. Starting from the rightmost digit and moving left, multiply the digits alternately by 3 and 1.
2. Add up the results.
3. Subtract the sum from the next multiple of 10. The result is the check digit (0 if the sum is already a multiple of 10).

For example, take the EAN-13 4006381333931. The first 12 digits are 400638133393. Multiplying them by 1, 3, 1, 3… from the left (which is 3, 1, 3, 1… from the right) gives 4 + 0 + 0 + 18 + 3 + 24 + 1 + 9 + 3 + 9 + 9 + 9 = 89. The next multiple of 10 is 90, so the check digit is 90 − 89 = 1, which matches the last digit of the barcode.

How do I convert a UPC or EAN to GTIN-14?

Add zeros to the left until the number has 14 digits. A 12-digit UPC-A gets two leading zeros, a 13-digit EAN-13 gets one, and an 8-digit GTIN-8 gets six. For example, the UPC 036000291452 becomes 00036000291452. The check digit doesn't change, because leading zeros add nothing to the sum. To go back from GTIN-14 to UPC or EAN, remove the leading zeros.

A GTIN-14 that starts with an indicator digit from 1 to 8 is different: it identifies another packaging level, such as a case or carton of the product. It's a new number, so its check digit has to be calculated again.

GTIN-8, UPC-A, EAN-13 and GTIN-14: which one do I need?

• UPC-A (GTIN-12) — the standard for retail products sold in the United States and Canada
• EAN-13 (GTIN-13) — the standard for retail products in the rest of the world
• GTIN-8 (EAN-8) — only for products too small to fit a full barcode
• GTIN-14 — for cases, cartons, and other packaging levels that aren't sold as single units at the checkout

For marketplace listings, use the GTIN printed on the item you sell. Google Merchant Center accepts all four formats, and Amazon listings usually use a UPC-A or EAN-13.

Can I look up a product by its GTIN?

Not with this tool. It checks that a GTIN is valid and shows the GS1 country prefix, but it doesn't return product data such as the name, brand, or description.

To see which company registered a GTIN, use GS1's Verified by GS1 service. It shows the brand owner and basic product information that the owner has shared with GS1.

If you need full product data for a whole catalog, Semantico can enrich your products from their GTINs at scale, with descriptions, attributes, and categories. Book a demo to see it on your own products.