Product Feed Identifiers Explained: GTIN, MPN, and EAN
If you manage a product feed for Google Shopping, you’ve seen the fields: GTIN, MPN, Brand. Very likely you’ve also seen Merchant Center warnings about missing or incorrect identifiers. These fields may seem straightforward, but getting them wrong can limit your product’s visibility, trigger disapproval, or quietly reduce your campaign performance.
This article breaks down what each identifier means, when to use which, and how they affect your Shopping campaigns.
What are unique product identifiers?
Unique product identifiers (UPIs) are standardised codes that tell Google exactly which product you’re selling. They allow Google to match your product listing with its global product catalogue, group the same item across different sellers, and serve the right ad to the right shopper.
The three primary identifiers Google uses are GTIN, Brand, and MPN. Each serves a different purpose, and each has specific rules about when and how to submit it.
GTIN: the universal product identifier
GTIN stands for Global Trade Item Number. It’s the most important product identifier in the Google Shopping ecosystem. A GTIN is a numeric code (8, 12, 13, or 14 digits) assigned by GS1, the international organization that governs barcode standards. Every product and product variant has its own unique GTIN.
The simplest way to think about it: a GTIN is the number printed under the barcode on the product packaging.
Depending on your region and product type, the GTIN may appear under a different name:
- EAN (European Article Number): 13 digits, standard across Europe
- UPC (Universal Product Code): 12 digits, used in North America
- JAN (Japanese Article Number): 8 or 13 digits, used in Japan
- ISBN (International Standard Book Number): 13 digits, used for books
- ITF-14: 14 digits, typically used for multipacks and cases
All of these are types of GTIN. When Google Merchant Center asks for a GTIN, you can submit any of the formats above. For European merchants, the EAN is the most common format.
Why GTINs matter for Shopping performance
When you submit a valid GTIN, Google can do several things it cannot do without one. It can match your product to its global catalogue. It can group identical products from different sellers for price comparison. It can display rich product information, including reviews and star ratings. And it can surface your listing more accurately against relevant search queries.
Products submitted without a GTIN (when one exists) will have limited visibility. Google is explicit about this: if your product has a manufacturer-assigned GTIN and you don’t include it, your ads may not be eligible for all Shopping placements.
With Google increasingly relying on AI to match products to shoppers, correct GTINs are becoming even more critical. AI-driven Shopping features depend on structured product data to understand what a product is, compare it against alternatives, and recommend it to the right buyer. Accurate GTINs are the foundation of that matching process.
Common GTIN mistakes
Submitting placeholder or fake GTINs. Google cross-references all GTINs against the official GS1 registry. Codes like “0000000000000” or random number strings will fail verification and may lead to product disapproval or account suspension.
Using the wrong GTIN for product variants. If you sell a shirt in three colours, each colour variant needs its own GTIN. Submitting the same GTIN for all three will cause mismatches.
Confusing internal SKUs with GTINs. Your internal stock keeping unit is not a GTIN. SKUs are specific to your business; GTINs are globally standardised. Never submit a SKU in the GTIN field.
Omitting GTINs for branded products. If you resell products from established manufacturers, those products almost certainly have GTINs assigned. Leaving the field blank when a GTIN exists limits your visibility and can flag errors in Merchant Center.
EAN: the European standard
EAN stands for European Article Number. In practice, EAN and GTIN are often used interchangeably in European e-commerce, which causes confusion. Here’s the distinction: EAN is a specific format of GTIN. An EAN is always a GTIN, but a GTIN is not always an EAN.
The standard EAN format is 13 digits (GTIN-13). It’s the most widely used barcode format outside of North America and the default identifier format for products sold across European markets.
If your product feed platform has a field labelled “EAN” rather than “GTIN,” you can map that directly to the GTIN field in Google Merchant Center. They’re the same underlying data.
The EAN is typically printed beneath the barcode on the product packaging. If you can’t find it on the packaging, you can request it from the manufacturer or distributor. Online barcode lookup services can also help verify EAN codes for specific products.
For private label or custom products where no EAN has been assigned, you can register with GS1 to receive your own valid GTINs. Never purchase GTINs from unofficial third-party resellers, as these may be recycled or unregistered codes that cause mismatches in Google’s catalogue.
MPN: the manufacturer’s internal identifier
MPN stands for Manufacturer Part Number. It’s an alphanumeric code assigned by the manufacturer to identify a specific product within their own catalogue. Unlike GTINs, MPNs are not standardised by a global organisation. Each manufacturer creates their own MPN format, which means two different manufacturers might use the same code for completely different products.
MPNs are useful in several situations. They help identify specific product models, versions, or configurations within a brand’s range. For technical products (electronics, auto parts, industrial equipment), the MPN is often the primary way buyers search for and identify exact items.
When MPN is required
Google’s rule is straightforward. If your product has a GTIN, submit it. The MPN is then optional but recommended.
If your product does not have a GTIN (for example, custom-made goods, vintage items, or niche products without barcode registration), then the MPN combined with the Brand becomes the required identifier pair.
The fallback hierarchy works like this:
- Product has a GTIN: Submit GTIN + Brand (MPN optional but recommended)
- Product has no GTIN but has a brand and MPN: Submit Brand + MPN
- Product has no GTIN, no brand, no MPN: Set identifier_exists to no
MPNs are usually listed on the product itself (often on a label on the side or bottom), in the manufacturer’s catalogue, on the manufacturer’s website, or in technical documentation. You can also request MPNs directly from the manufacturer.
Important: do not invent MPNs. If you don’t have one, leave the field blank rather than populating it with a SKU or random value. Incorrect MPNs can cause product mismatches and disapprovals.
How identifiers work together
Google recommends submitting all three attributes (GTIN, Brand, and MPN) whenever possible, even when only one or two are strictly required. Each identifier adds a layer of matching accuracy.
Think of it this way. Brand tells Google who made the product. GTIN tells Google exactly which product and variant it is. MPN tells Google which model or part number within the manufacturer’s catalogue it corresponds to. Together, they eliminate ambiguity.
This matters most when multiple sellers list the same product. Google uses these identifiers to group identical products, compare prices, and display aggregated reviews. Merchants with complete and correct identifiers will be prioritised over those with missing or incorrect data.
Identifier requirements by product type
| Product type | GTIN | Brand | MPN | identifier_exists |
|---|---|---|---|---|
| Branded product with barcode | Required | Required | Recommended | Do not set |
| Branded product without barcode | Not required | Required | Required | Do not set |
| Custom/handmade product | Not required | Use store name | Optional (create your own) | Set to no |
| Books | ISBN (required) | Not required | Not required | Do not set |
| Multipacks (manufacturer-created) | Use multipack GTIN | Required | Use multipack MPN | Do not set |
| Refurbished/used products | Use original GTIN | Required | Recommended | Do not set |
Feed quality and campaign performance
Getting identifiers right is a fundamental of feed hygiene that directly impacts campaign performance. Products with correct GTINs receive better placement in Google Shopping results. They’re eligible for features like price comparison, product reviews, and rich product information. They match more accurately to relevant search queries.
For merchants running campaigns through a CSS partner like Shoparize, feed quality is the foundation of everything. We manage Shopping campaigns on a pay-per-sale basis across Google Shopping, Microsoft Shopping, and Shoparize.com for 25,000+ merchants. When product identifiers are incorrect or missing, it limits the auction coverage our campaigns can achieve for your products. Correct identifiers mean more eligible auctions, better matching, and stronger incremental performance.
If you’re unsure about the quality of your product identifiers, start with a simple audit:
- Check GTIN coverage. What percentage of your products have a GTIN submitted? For branded products, this should be close to 100%.
- Validate existing GTINs. Use the GS1 check digit calculator to verify that submitted GTINs are correctly formatted.
- Review Merchant Center diagnostics. Google flags identifier issues in the Diagnostics section. Look for warnings about missing GTINs, mismatched identifiers, or incorrect identifier_exists values.
- Audit MPN and Brand completeness. For products without GTINs, ensure Brand + MPN are both submitted correctly.
Summary
Product identifiers are a small part of your feed setup that has an outsized impact on Shopping performance. GTIN is the most important: it’s the globally standardised code that tells Google exactly what your product is. EAN is the European variant of GTIN, and the two terms are effectively interchangeable for European merchants. MPN is the manufacturer’s internal code, useful as a secondary identifier or as a fallback when no GTIN exists.
The rule of thumb: submit every identifier you have. Ensure they’re accurate. Never fabricate, guess, or reuse codes from similar products. And audit your feed regularly to catch issues before they limit your campaign performance.
Looking for more insights on how feed optimisation impacts your campaigns, or want to see how a managed, pay-per-sale CSS layer can help you grow your Google Shopping, reach out to our team. Ready to get started right now? Start here.
