Category IDs are useful when troubleshooting imports, integrations, custom modules and catalog logic. The Admin path differs between current Magento 2 and historical Magento 1, so the version matters.
Magento Open Source 2.x and Adobe Commerce
In Admin, go to Catalog > Categories. Select the category in the tree. The category identifier is shown with the selected category in the page header; the exact label or placement can vary slightly by release, but the numeric ID belongs to that category in that Magento installation.
Do not copy a category ID from another environment and assume it matches production. IDs can differ between installations even when category names are the same.
Magento 1 is historical
Older Magento 1 instructions used Catalog > Manage Categories. Keep that wording only when maintaining a Magento 1 archive or migration reference; it should not be presented as the current Magento 2 Admin path.
Retrieve category IDs through the Magento 2 REST API
For integrations or repeatable diagnostics, the Magento 2 category tree endpoint can return IDs programmatically. An authenticated request can use a store-code route such as GET /rest/default/V1/categories. The response contains category nodes with fields including id, parent_id, name and child data.
Use the credentials and ACL appropriate to the environment, and match by the expected tree/path rather than category name alone when names are duplicated.
Expected result and common mistakes
The result should be one numeric ID tied to the intended category in the target environment. If an import or customization still fails, verify the category exists in the correct root/store context and that the integration is not using an ID copied from a different database.
Need help with Magento catalog logic?
If category IDs are only one symptom of a larger import, integration or custom-code problem, share the affected store flow and expected catalog behavior.