MPN Attribute in Google Shopping: Manufacturer Part Numbers Explained

What is the MPN attribute?

The mpn (Manufacturer Part Number) attribute contains the unique identifier assigned by a product’s manufacturer to identify that specific product within their own catalogue. It is one of three product identifiers Google uses — alongside gtin and brand — to match your listing against its global product catalogue and aggregate data from multiple merchants selling the same item.

Unlike GTIN, which is a globally standardised barcode system (EAN, UPC, ISBN), MPNs are specific to each manufacturer — there’s no cross-manufacturer standardisation. The same MPN “CF226A” only means something in the context of HP. This is why MPN is almost always submitted together with the brand attribute: brand + MPN together form a unique product identifier pair that Google can use for catalogue matching.

Technical specifications

Where MPN is used

• Product catalogue matching — Google uses MPN + brand to identify the exact product and match it against its internal product knowledge graph. This enables richer listings and review aggregation even for products without GTINs.

• Review aggregation — When Google can confidently identify a product via MPN + brand, it aggregates reviews from across the web — Google Shopping, third-party review sites, and merchant reviews — into a unified rating for the product.

• Price comparison — Accurately identified products (via MPN or GTIN) are eligible for Google’s price comparison features, where your price is shown alongside other merchants selling the same item.

• Auction priority — Products with complete identifier sets (GTIN and/or MPN + brand) receive higher priority in Shopping auctions than products with incomplete identifiers.

• Free Listings quality — For Free Listings on the Shopping tab, product identification quality directly affects ranking. MPN improves identification confidence where GTIN is absent.

MPN vs. SKU vs. GTIN — when to use which

Rules

• Use the manufacturer’s exact part number — do not invent or modify it

• Always submit brand alongside mpn — MPN alone is not a globally unique identifier

• Do not use your internal SKU, barcode, or inventory number as an MPN

• For products with a valid GTIN: GTIN takes precedence. Submit both where available, but GTIN + brand is a stronger identifier set.

• If a product has no MPN: omit the field (do not use placeholder values like “N/A” or “none”)

• If a product has neither GTIN nor MPN: set identifier_exists to false

• Do not reuse the same MPN for different variants — each physical variant should have its own MPN if the manufacturer assigns distinct part numbers per variant

Best practices

• Always pair MPN with brand — MPN alone gives Google an incomplete identifier. Brand + MPN together form a fully qualified identifier for catalogue matching.

• Source MPNs from the manufacturer — Do not rely on how a distributor or previous supplier labelled the part. Always verify against the manufacturer’s official documentation or product page.

• Include MPN in title for B2B and industrial products — Buyers of spare parts, components, and industrial supplies often search by MPN directly. Including the MPN in both the mpn field and the title captures these high-intent direct-MPN searches.

• Maintain a clean MPN mapping in your PIM — MPNs can change when manufacturers update product lines. Audit your MPN data periodically against manufacturer catalogues, especially for long-running product lines.

• For spare parts and accessories — The MPN should be the part’s own MPN, not the MPN of the parent product it fits. If you also submit compatibility information, use the product_detail or description fields.

Impact on performance

• Review star aggregation — Correctly matched products via MPN accumulate reviews from across the web. Review stars measurably increase CTR in Shopping results — typically 10–25% uplift depending on category.

• Improved auction position — Products with complete identifier sets (GTIN or MPN + brand) receive higher bidding priority in Google’s auction, often translating to lower CPC for equivalent positioning.

• Price comparison eligibility — Only products Google can positively identify appear in price comparison features. MPN enables this for products without GTIN.

• Long-tail MPN searches — Including MPN in title (for applicable categories) captures searches for the specific part number, which tend to have very high purchase intent and low competition — excellent ROAS.

Common mistakes

• Submitting your internal SKU as the MPN (SKU is an internal identifier, not a manufacturer part number)

• Omitting the brand attribute when submitting MPN (makes MPN meaningless for matching)

• Using a generic placeholder value like “N/A”, “none”, or “000” in the MPN field

• Using the GTIN/EAN in the MPN field and vice versa (these are separate attributes for a reason)

• Reusing the parent product’s MPN for all its variants when the manufacturer assigns distinct MPNs per variant

• Using the distributor’s catalogue number instead of the manufacturer’s actual MPN

Pro tips

• Use manufacturer API data sources where available — Some manufacturers expose product data APIs or partner with data aggregators (e.g., Akeneo, Syndigo, Salsify) that include verified MPNs. Feeding from these sources eliminates manual MPN entry errors at scale.

• Monitor MPN mismatch warnings in Diagnostics — GMC’s Diagnostics tab flags products where the submitted MPN doesn’t match the expected MPN for the declared brand+GTIN combination. These warnings indicate data quality issues that affect catalogue matching.

• For automotive parts: use ACES/PIES compatibility data — Automotive parts have an industry-standard data format (ACES for fitment, PIES for product attributes) that includes validated MPNs. Many aftermarket parts suppliers can provide ACES/PIES exports. This data is significantly more reliable than manual MPN entry for vehicle parts catalogues.

• Build MPN validation into your feed pipeline — Write a simple validator that checks MPN length (1–70 characters), rejects known placeholder strings (“N/A”, “NONE”, “0000000000”), and flags suspiciously duplicate MPNs across different products. Catching these upstream prevents feed quality degradation at scale.