ASIN

The ASIN (Amazon Standard Identification Number) is the number under which Amazon lists a product in its own catalogue. It consists of ten characters, a mix of letters and digits, and for most products begins with "B0"; for books it begins with a digit. The ASIN is an Amazon-specific catalogue number and not an international standard like the GTIN and EAN.

Where to find the ASIN

• In the product page's address: the ten characters after "/dp/" are the ASIN.
• On the product page in the product information section.
• As a seller in Seller Central in your inventory overview, next to each offer.

Who assigns the ASIN

Amazon. When a seller creates a new product page, Amazon assigns it a new ASIN. If the product already exists in the catalogue, no second page is created: under Amazon's ASIN creation policy, you then match your offer to the existing ASIN. All sellers of the same product therefore share one ASIN and one product page.

For a new product page, Amazon requires a product ID in most categories, usually an EAN or a UPC. Amazon checks these numbers against the GS1 database; numbers that do not match there are treated as invalid. If a product has no ID, a GTIN exemption may be an option, which Amazon grants for example for private-label products without a barcode, handmade products or bundles; some categories require no product ID at all.

An ASIN cannot be calculated from an EAN. To check whether a product page already exists for your EAN, search for the product ID under "Add Products" in Seller Central.

ASIN, SKU and EAN: which number stands for what

In Amazon's API documentation, your offer is identified by your SKU and the catalogue entry by the ASIN. Amazon merges the details from one or more offers into a single catalogue entry under the ASIN. That is why one ASIN can have several SKUs in your account, for example if you offer the same item via FBA and FBM (merchant-fulfilled). For your analysis this means: anyone who only totals per ASIN mixes the costs of both fulfilment routes.

The FNSKU is added with Fulfilment by Amazon. It is Amazon's own barcode, begins with "X" and identifies goods in the fulfilment centre when the manufacturer barcode is not used. Since 31 March 2026, according to Amazon's help pages: resellers use Amazon barcodes even if a manufacturer barcode is available; brand owners can continue to use the manufacturer barcode.

Parent and child ASINs for variations

Amazon groups variations such as size or colour on one product page. Behind this are two kinds of ASINs:

• Parent ASIN: a virtual ASIN that only links the variations together. It is not a purchasable item and has no inventory.
• Child ASIN: the purchasable variation, for example "T-shirt, blue, size S". Each variation has its own ASIN.

So what is sold is always the child ASINs with their SKUs. If you want to assess a model across all sizes and colours, you group the variations via the parent ASIN or your own product group. Under Amazon's policies, a variation family may only contain products with the same function, the same brand and the same product type; attaching newer models or sets that do not come from the manufacturer as a variation is not permitted.

Typical problems from a seller's perspective

The same product under several ASINs

Duplicate product pages arise when a product is created a second time. For this, Amazon offers a self-service tool in Seller Central for merging duplicate product pages. The requirements according to Amazon:

• Both products are identical, all attributes match, including the product ID.
• You have active offers for the ASINs.
• Parent ASINs and ASINs of different brands cannot be merged. ASINs from Brand Registry can only be merged by the holder of the brand rights.

Afterwards, the target ASIN is the main offer, buyers of the old page are redirected, and the inventory and sales history of the source ASIN appear under the target ASIN. Reports you have already downloaded still carry the old number. Comparisons over longer periods are therefore only correct if you map both ASINs to the same item.

New ASIN after a brand or product change

Some details can no longer be changed once an ASIN has been created, according to Amazon for example the GTIN and the number of units per pack. If the brand name changes, Amazon requires a new ASIN and recommends linking the old and new page via the "Newer Version" widget. In that case, too, two ASINs belong to one item that you continue to manage internally as one.

The EAN matches someone else's product

If Amazon reports a conflict with an existing ASIN when you create a listing, first check whether the product found is really yours. As a common cause, Amazon names manufacturers that reuse codes, in the fashion industry for example after three years; to resolve it, Amazon requires proof such as the GS1 certificate. Under GS1's rules, a GTIN that has been assigned may, as a rule, no longer be allocated to any other product since 1 January 2019.

The ASIN when selling across several channels

Only Amazon assigns the ASIN. OTTO, Kaufland and bol.com require an EAN for their products, and eBay requires product identifiers such as GTIN, brand and manufacturer part number in certain categories. Anyone selling the same item on several channels therefore needs a number that appears everywhere: the EAN or your own SKU. The ASIN belongs in your own product list as an additional column. How the EAN and SKU work as a bridge between the channels and where they reach their limits is explained under GTIN and EAN.

Sources (accessed 17 September 2026): Amazon, What is an ASIN; ASIN creation policy; Product UPCs and GTINs; Listing products without a product ID; Selling Partner API, Terminology; Barcode requirements for Fulfilment by Amazon; Product variations overview; Merge duplicate product pages; Error 8541; GS1 Germany on the GTIN.