What is an MPN in Google Merchant Center?
WeAdU · Updated 19 October 2026
An MPN (Manufacturer Part Number) is the manufacturer's reference for a product. In Google Merchant Center, the mpn attribute receives that reference: it is required when the manufacturer assigned no GTIN, and optional for a custom item or one with no clear reference.
When should mpn be filled in?
In Merchant Center, the mpn attribute receives this reference. It is required when the manufacturer assigned no GTIN, and optional for a custom item or one with no clear reference. A wrong value gets the product disapproved. Do not guess it. Unless you are the manufacturer, do not put a code created for the store there, or an internal SKU you are not sure of.
If codes exist but are unknown, leave mpn empty, and do not drop the store SKU into it. If no code exists, send neither gtin, nor brand, nor mpn. A manufacturer who is also the only seller, and who assigned no reference, may submit a number of their own choosing. With no official brand, the store name is used as the brand. These rules come from the attribute and specification pages read on 2 October 2026.
What does identifier_exists do for the MPN?
The identifier_exists attribute is optional. Its default is yes. The value no is for media with no GTIN, apparel with no brand, or, in other cases, an item with no GTIN and no MPN tied to a brand. With no, send the codes you have. A product that has codes, submitted as no, receives a warning.
Which reference for a variant or a bundle?
Each variant usually has its own MPN. Sizes of the same garment often share one. Different colours have distinct references. A manufacturer bundle carries the bundle's reference. A bundle built by the store carries the main product's. The same split applies to a multipack. A compatible carries its own manufacturer's reference, not the original brand's. A made-to-order item, with no clear reference, can leave the attribute empty.
What does the WeAdU audit cover?
All our audits cover Google Ads only. This page defines the reference. It does not promise that an empty field, or a filled field, changes serving.
Help pages
Google help pages read on 2 October 2026.