# What is a GTIN?

> A GTIN is the barcode number that identifies a product. Learn the valid lengths, why Google and Meta ask for it, and the mistakes that get products flagged.
> Published: 2026-10-14
> Updated: 2026-10-14
> Canonical: https://rabbot.ai/glossary/gtin/

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A GTIN (Global Trade Item Number) is the number printed under a product's barcode. It identifies one product in a way that shopping channels can match against their own catalogues. UPC and EAN are the best-known formats of the same number, and Google accepts GTINs of 8, 12, 13 or 14 digits.

## Why it matters for a Shopify store

Google Merchant Center and Meta both ask for a GTIN in your product data. Google states that products with missing or incorrect GTIN attributes may have limited visibility. Meta lists the GTIN as recommended rather than required, and says it helps classify the item.

In Shopify the number normally lives in the barcode field of each variant. A feed built from your store copies that field into the `gtin` attribute. If the barcode field is empty or holds an internal code, the feed carries the same gap to every channel.

## Formats Google accepts

Google lists these formats:

- UPC (North America, 12 digits). An 8-digit UPC-E code must be converted to 12 digits.
- EAN (Europe) is 13 digits.
- JAN (Japan, 8 or 13 digits).
- ISBN, for books, is 13 digits, so convert an ISBN-10 to ISBN-13.
- ITF-14 for multipacks, 14 digits.

Spaces and dashes are ignored. Meta asks you to leave them out.

## How it commonly goes wrong

Google's help page names these problems:

- The check digit is missing or wrong. Google says the check digit must be present and correct.
- The number starts with a restricted prefix (02, 04 or 2) or a coupon prefix (05, 98 or 99).
- One GTIN is reused across several products with identical variant attributes in the same country and language.
- A variant, such as a size or colour, shares the GTIN of its parent instead of having its own.
- A GTIN is made up for a product that has none. Google says to leave the value out if you are unsure, and to send brand and MPN for products without a manufacturer-assigned GTIN, such as many private-label items.

Meta gives similar advice: only provide a GTIN if you are sure it is correct, and send an MPN when there is no GTIN.

## Where Rabbot fits

Rabbot's feed cross-check reads required identifiers such as barcodes against your live pages and raises a gap as disapproval risk. Free runs the cross-check once at install, and paid plans run it every day. [What feed monitoring is](/docs/feeds/what-feed-monitoring-is/) explains both layers.

## Related terms

A GTIN is one attribute inside a [product feed](/glossary/product-feed/). A bad one is a common reason for a [disapproved product](/glossary/disapproved-product/). A [supplemental feed](/glossary/supplemental-feed/) is one way to correct identifiers without rebuilding the main feed.

## Sources

- [Google Merchant Center Help: GTIN [gtin]](https://support.google.com/merchants/answer/6324461)
- [Meta for Developers: catalog fields, GTIN, brand and MPN](https://developers.facebook.com/docs/commerce-platform/catalog/fields)