MPN (manufacturer part number)

An MPN (manufacturer part number) is the code a manufacturer assigns to identify one product among all the products it makes.

By Berend Vrakking, founder of Product Metrics. Updated 7 October 2026.

Example

Identifier fields for four products
Product	brand	gtin	mpn	identifier_exists
Trail Runner 2, black, size 42 (resold)	Example Brand	8712345678906	TR2-2026-BLK-42	leave out
Replacement filter F20 (no GTIN)	Example Appliances	leave out	F20-0415	leave out
Linen apron, sage (you make it, only you sell it)	Your store name	leave out	APR-LIN-SAGE	leave out
Custom-printed T-shirt (one-off)	leave out	leave out	leave out	no

The first two rows carry the manufacturer’s own codes. The apron is the exception: as its manufacturer and only seller, you use your store name as the brand and an MPN of your choice. The T-shirt has no identifiers, so identifier_exists is no. Illustrative data.

For one product, and for an account

An MPN is unique only among one manufacturer’s products, so it identifies a product together with its brand. It usually belongs to one variant: Merchant Center notes that each colour or size typically has its own MPN, although apparel sizes often share one.

Merchant Center requires an MPN for every product without a manufacturer-assigned GTIN, and products that have a brand and MPN but are submitted without them may have limited visibility.

Identifiers also decide which shops sell the same product. Competitor Prices treats products as identical when they share a product id, GTIN or EAN. Own-brand products share no identifier with competitors, so it compares them on the dimensions you approve, such as style and colour.

Common mistake

Putting your own SKU in the mpn field for a product someone else makes. Merchant Center wants the manufacturer’s MPN: no internal SKUs or other store-specific values, and no identifiers made up, guessed or copied from similar products.

Questions

What is an MPN number on a product?

Look on the packaging or the manufacturer’s site: it is usually a mix of letters and digits. Merchant Center accepts 1 to 70 characters, and its own example pairs the brand Google with the MPN H2G2-42.

What is the difference between an MPN, a GTIN and a SKU?

A GTIN is the global number behind the barcode, the same for every shop that sells the product. An MPN is the manufacturer’s code, unique only within that brand. A SKU is the code you create for your own stock, so it differs from shop to shop.

Is an MPN required in Google Merchant Center?

Only for products without a manufacturer-assigned GTIN. It is optional for products with no clearly associated MPN and for custom-made items such as art or handmade goods. If a product has no GTIN, MPN or brand at all, set identifier_exists to no, and only when you are certain: a product wrongly marked no gets a warning.

Sources

Keep reading

GTINThe barcode number Merchant Center asks for first; the MPN fills in when there is none.
Product feedThe data source where the mpn, brand and gtin of every product sit.
Google Merchant CenterWhere missing or incorrect identifiers show up as warnings and disapprovals.
Supplemental feedA second data source that adds to or overrides attributes in the primary feed.
Competitor PricesHow products are compared when they share an identifier, and when they do not.