Amazon asks for a product ID. You enter the code from your stock spreadsheet, but the listing does not move forward. The problem may be simple: the number that identifies your inventory is not necessarily the number that identifies the product.
A GTIN identifies a product across commerce, an ASIN identifies it in Amazon’s catalog, and a SKU identifies inventory within a seller’s system. A UPC is a type of GTIN. These terms are related, but they are not interchangeable. Amazon’s GTIN guide explains the product-ID role.
Which identifier answers which question?
GTIN / UPC: The specific product. Which item is this across retailers?
ASIN: The Amazon catalog product. Which Amazon detail page describes this item?
Seller SKU: Your inventory or offer. How does my business track this stock?
Consider a blue shirt in a small size. Its product identifier should refer to that particular version. The medium version is a different variation. Your internal codes might be BLUE-S and BLUE-M, but inventing those SKUs does not create valid product identifiers.
Check the product before copying its barcode number
Start with the actual packaging and the supplier’s product information. Make sure the identifier belongs to the correct brand, model and version. If you are listing a pack, do not assume the identifier for one loose unit also describes the pack.
Our recommendation is to keep one mapping table with your SKU, the supplier’s identifier, the exact variant and any matched ASIN. It gives you a quick way to spot when two different products have accidentally been assigned the same information.
Search the catalog before creating something new
Amazon’s Seller University course explains that product identifiers help connect an offer to an existing catalog product. When the exact product is already listed, you may be adding an offer rather than creating another product page.
Search using the identifier, then compare the result with your item. If the brand or quantity does not match, pause. Copying an ASIN from a near-match simply moves the problem into your live listing.
What if the product has no UPC?
A missing UPC does not automatically mean you qualify for a GTIN exemption. Amazon describes an exemption process for eligible products. Check the current requirements and the prompts in your listing workflow before assuming your product qualifies. The official GTIN guide is a useful starting point.
The supplied training mentions examples such as certain handmade or private-label items without a manufacturer-provided ID. Treat these as situations to investigate, not blanket approvals. Being handmade, having your own brand or selling a bundle does not by itself settle the exemption question.
Diagnose the error before changing identifiers
When a listing fails, save the exact message and note which field triggered it. Then check whether you entered a seller SKU into a product-ID field, selected the wrong identifier type, copied a number incorrectly or matched the wrong variant.
We recommend fixing one confirmed issue at a time. Randomly switching brands, categories and IDs makes it harder to understand what caused the original rejection.
Common product-ID questions
Can I use an ASIN instead of a UPC?
They serve different purposes. An ASIN can help identify an existing Amazon catalog item, but it does not become a universal product identifier for a genuinely new product.
Can every color and size share one product ID?
The training describes distinct identifiers for distinct variations, such as different shirt sizes and colors. Check the requirements for the specific products you are listing.
Written for Amazon US sellers by GoofProof eCom. Based on reviewed Amazon Seller University materials and the official guidance linked above. Source review: October 1, 2026. Check the current Seller Central requirements for your product and account.
