Google changes in March 2026: how to get GTINs and product IDs right

From March 2026, Google is expected to enforce a change to how multi-channel products are handled. If the same item differs online and in store, for example on price, availability or condition, it should be submitted as two products with separate product IDs.

Google’s Help Centre sets out the updated multi-channel product system, and industry coverage points to March as the enforcement window. 

With this in mind, we recommend that you review how you structure product data now, not later.

On Google, product identity drives both eligibility and performance. Google’s guidance is unambiguous about Global Trade Item Numbers (GTINs).

There is a useful performance benchmark as well. Matt Lawson, then director of performance ads marketing at Google, noted that providing the correct GTIN “can increase the conversion rate for that product by up to 20 per cent”, based on internal analysis of advertisers who added GTINs. Results will vary, but it is a clear signal that identity affects outcomes.

Start with the identifiers. Submit the GTIN wherever one exists and pair it with brand and, where appropriate, MPN. Use accepted formats such as EAN GTIN13, UPC GTIN12, JAN, ISBN13 and ITF14 for multipacks. Do not invent values and do not reuse internal SKUs in place of a GTIN. If a GTIN does not exist, follow Google’s guidance for products without assigned identifiers rather than guessing. 

Restructure multi-channel products where needed. If an item truly differs online and in store, create distinct product entries with different IDs and manage them separately. This prevents conflicting attributes surfacing across Shopping, free listings and local inventory, and aligns with Google’s updated multi-channel model. 

Expect a few snags during tidy up. A common one is “product ID already used” when a local only product clashes with a multi-channel product that shares the same ID, content language and feed label. Google provides a clear fix to separate the entries across destinations, so it is worth addressing this early. 

Keep to the specification. Titles, price, availability and identifiers should follow the product data specification to avoid disapprovals or limited serving. Use Diagnostics and the Issue Details view in Merchant Centre to pinpoint and resolve problems as you go. 

Help teams find legitimate codes. Google explains where GTINs appear on packaging and which code types apply in different regions. If a manufacturer has assigned a GTIN, use that value rather than an internal code.

The GTIN is a GS1 identifier. Using it correctly ensures each trade item is uniquely and reliably identified across systems and sales channels. GS1 UK members can publish the seven foundational attributes from My Numberbank to the GS1 global registry so retailers and marketplaces can verify identity through Verified by GS1. This reduces duplication and catalogue mismatch, two common causes of feed friction at scale.

Begin with a catalogue export and confirm which products have manufacturer GTINs. Correct formats, remove guesses and fill gaps. Identify products sold online and in store where price, availability or condition differ, then split them into separate product IDs and align destinations and feed rules. Work through Diagnostics to clear identifier warnings and fix any “product ID already used” issues, then resubmit and monitor. Finally, publish core attributes via My Numberbank to support verification and add a light pre-launch check so new products arrive with correct GTINs, attributes and IDs from day one.