item_group_id is a value shared by every variant of one product and by nothing else, up to 50 characters, required for variants in free listings and in Shopping ads for Brazil, France, Germany, Japan, the United Kingdom and the United States. With it, Google shows the variants as one product with a picker; without it, each size competes as a separate product.
| Attribute | item_group_id |
|---|---|
| Requirement | Required for product variants in free listings and in Shopping ads for Brazil, France, Germany, Japan, the United Kingdom and the United States; recommended otherwise. |
| Format |
|
Google’s rules for item_group_id
- Every variant keeps its own id; the group id is what they share.
- Variants in a group should differ in an attribute Google reads: color, size, material, pattern.
- The parent product’s id or handle is the natural value.
Common mistakes, and the error each one becomes
- Variants exported with no group at all. → Missing value [item_group_id]
- The parent’s id written as each variant’s id instead of as the group. → Reused value [id]
- Grouped variants with identical images across colours. → Same value for differing variants [image_link]
Where the value comes from on a connected store
| Shopify | The product id, on every variant row. |
|---|---|
| WooCommerce | The parent product’s post id on every variation row; omitted for simple products. |
The free feed check reads this attribute from any feed file and reports the defects above; every check is listed.
Questions merchants ask
Do single products need item_group_id?
No. Only variants. Leaving it empty on products without variants is correct.
Can Meta use the same value?
Meta requires that no product id equals any item_group_id, so a feed that sends the parent as a product and as the group conflicts there. Send variants only, or prefix the group.
My variants are grouped but still show separately. Why?
Google tells variants apart by their attributes. If the rows in a group do not differ in color, size, material or pattern, there is nothing to pick between.
Sources
- Item group ID [item_group_id] — Google Merchant Center Help
- Product data specification — Google Merchant Center Help