Manufacturer part number

What does Google need the MPN for?

Google’s Merchant Center help states that the MPN is required for all products without a manufacturer-assigned GTIN. It is optional for custom-made items such as art or handmade goods. The attribute allows up to 70 characters. The help page says to provide an MPN only when you are sure it is correct and not to guess or make up a value. For new products without assigned product identifiers, the identifier_exists help page says to submit identifier_exists as “no”.

For variants, each normally has its own MPN, although different sizes of apparel often share one. For bundles and multipacks the manufacturer’s MPN applies if the manufacturer created the bundle. If you assembled it yourself, use the MPN of the main product.

In Product markup, mpn is a recommended property alongside gtin and sku.

According to Google, an MPN uniquely identifies a product among all products from the same manufacturer. It is therefore not necessarily unique across manufacturers and is normally paired with the brand (an assessment). A SKU, by contrast, is a number a seller defines for its own inventory, and a GTIN is a globally unique number.

Example

{
  "@type": "Product",
  "name": "Brake disc 280 mm",
  "brand": { "@type": "Brand", "name": "Example Brand" },
  "mpn": "BD-280-FA"
}

FAQ

What is the difference between GTIN and MPN? A GTIN is unique worldwide and used across retail. An MPN is the manufacturer’s own number and identifies a product reliably only together with the brand.

What is the difference between a SKU and an MPN? A SKU is the seller’s internal code for inventory. An MPN is assigned by the manufacturer and stays the same across sellers.

Last updated: October 7, 2026