What is a GTIN and do I need one?

A GTIN (Global Trade Item Number) is the standardized barcode number for a product — UPC, EAN, or ISBN are all GTIN formats. If your products have manufacturer-assigned GTINs, Google strongly recommends including them; they improve match rates and Shopping eligibility. Custom or handmade products without a GTIN can use brand plus MPN instead.

Where does WooCommerce store GTIN?

Recent versions of WooCommerce include a GTIN, UPC, EAN, or ISBN field on the product's Inventory tab. Older stores often store identifiers in a custom field or via a plugin. Storing the value is only half the job — it also has to be emitted into your Product schema and product feed.

What if my products don't have a GTIN?

Use brand plus MPN (Manufacturer Part Number). For genuinely unique items like handmade goods, you can set identifier_exists to false in your feed. Never invent or reuse GTINs — incorrect identifiers cause disapprovals.

Guides / GTIN, brand & MPN

How to Add GTIN, Brand & MPN to WooCommerce Products

Product identifiers are the single most under-used lever in WooCommerce SEO. They tell Google exactly which product you’re selling, unlock Shopping eligibility, and help AI engines cite you accurately. Here’s how to get them right.

The three identifiers that matter

Identifier	What it is	Example
GTIN	Global Trade Item Number — the barcode number (UPC, EAN, ISBN are all GTINs)	`0012345678905`
Brand	The manufacturer or brand name	`TrailMaster`
MPN	Manufacturer Part Number — the maker’s own SKU	`TM-BP-30L`

The general rule from Google: provide GTIN + brand when a product has a barcode, and brand + MPN when it doesn’t.

Why they matter so much

Shopping eligibility. Missing identifiers are a leading cause of Merchant Center disapprovals and limited reach.
Accurate matching. A GTIN lets Google connect your listing to the canonical product, its reviews, and price comparisons.
AI citation. Answer engines trust unambiguous identifiers; they reduce the chance an AI confuses your product with another.

Where WooCommerce stores them

Recent WooCommerce versions add a GTIN, UPC, EAN, or ISBN field under each product’s Inventory tab. Brand may come from a product attribute, a dedicated brand taxonomy, or a plugin. MPN is usually a custom field. The catch: storing a value is not the same as publishing it. The identifier has to make it into two places to actually help you:

Your Product schema (JSON-LD on the product page)
Your product feed (Merchant Center, Bing, Meta, etc.)

What it looks like in schema

{
  "@type": "Product",
  "name": "TrailMaster Waterproof Backpack",
  "brand": { "@type": "Brand", "name": "TrailMaster" },
  "gtin13": "0012345678905",
  "mpn": "TM-BP-30L",
  "offers": {
    "@type": "Offer",
    "price": "89.00",
    "priceCurrency": "USD",
    "availability": "https://schema.org/InStock"
  }
}

Use the GTIN property that matches the length: gtin12 for UPC, gtin13 for EAN, gtin14 for ITF-14, or the generic gtin.

What it looks like in a product feed

<g:brand>TrailMaster</g:brand>
<g:gtin>0012345678905</g:gtin>
<g:mpn>TM-BP-30L</g:mpn>

Common mistakes to avoid

Inventing GTINs. Never make one up or reuse another product’s. Invalid GTINs fail Google’s checksum and get disapproved.
Storing but not emitting. A value in the Inventory tab that never reaches your schema or feed does nothing for SEO.
Wrong GTIN length. Mismatched gtin12/gtin13 properties trigger validation warnings.
Forgetting variants. Each variation often has its own GTIN; don’t apply the parent’s to all.

Doing it without custom code

Mapping identifiers into both schema and feeds — consistently, across every product and variation — is exactly the kind of repetitive plumbing that’s easy to get wrong by hand. Easy Woo API reads your stored identifiers and emits them into clean Product schema and feed-ready endpoints automatically, so the same correct value appears everywhere.

Next: see the full Product schema guide and Google Merchant feed guide.