Definition
The ASIN is a 10-character identifier Amazon assigns when a product is listed. The format is typically "B0" followed by eight alphanumerics (e.g., B08N5WRWNW), except for books, where the ASIN equals the ISBN-10. ASINs are scoped per Amazon region — the same physical product on amazon.com and amazon.co.uk carries different ASINs, though they often share a parent ASIN relationship.
Multiple related variants (color, size, pack size) usually roll up under a parent ASIN, with each variant carrying its own child ASIN. Reviews are stored at the child level but surfaced across the parent on the product page, which is why a single Amazon listing sometimes shows reviews that describe a variant the shopper isn't looking at.
How to find an ASIN
The fastest way is the product URL. On any Amazon listing the ASIN is the ten characters directly after /dp/ or /gp/product/ — in amazon.com/dp/B08N5WRWNW, the ASIN is B08N5WRWNW.
It is also printed on the listing itself, in the "Product information" or "Additional Information" table near the bottom of the detail page, on a row labelled ASIN. For books there is no separate code to look up: the ASIN is the ISBN-10, which is on the copyright page and usually the back cover.
Sellers see their own ASINs in Seller Central under Inventory, alongside the seller SKU they set themselves. A brand auditing its catalogue normally needs that pairing rather than either code alone, because one internal SKU can sit behind several ASINs.
ASIN vs SKU, UPC, and GTIN
These four get used interchangeably and are not interchangeable. The distinction that matters is who issues the code and how far it travels.
| Identifier | Assigned by | Scope | Format |
|---|---|---|---|
| ASIN | Amazon | One per listing, per Amazon marketplace | 10 alphanumeric characters, usually starting B0 |
| SKU | The seller or brand, internally | Whatever that business decides | No standard — each company sets its own |
| UPC | GS1, licensed to the brand | Global, one per sellable unit | 12 digits |
| GTIN | GS1 | Global — the umbrella standard covering UPC, EAN and ISBN | 8, 12, 13 or 14 digits |
So an ASIN is Amazon's internal key and exists nowhere else; a UPC identifies the same physical unit on any retailer's shelf; and a SKU is whatever the brand chose to call it. A product sold on Amazon, Walmart and Best Buy carries one UPC and three different retailer identifiers, which is why SKU-level analytics depends on mapping between them rather than picking one.
Why it matters
For consumer brands, the ASIN is the primary key for feedback analysis on Amazon — the single largest review channel by volume for most physical products. Linking an ASIN to an internal SKU, UPC, and Model# is the hard part of consumer-brand VoC work: retailers maintain their own identifier schemes, and a single product SKU often appears under multiple ASINs (one per variant, one per fulfillment arrangement, one per legacy listing).
Without ASIN-to-SKU mapping, review sentiment cannot be rolled up per product, warranty data cannot be cross-checked against review themes, and launch monitoring is limited to what any single ASIN captures.
Example
A kitchen appliance brand sells a blender with internal SKU BLD-4200-BLK on amazon.com. The listing has one parent ASIN and three child ASINs covering black, red, and white variants. Each child ASIN collects reviews independently. The brand also sells the same black variant through Amazon Business under a separate ASIN, and an older 4100 model that Amazon has not removed still attracts "wrong model" reviews against the 4200 listing.
A VoC platform that handles ASIN-to-SKU linking maintains the full mapping: four ASINs (one parent, three children) plus the Amazon Business ASIN plus the legacy 4100 ASIN, all rolled up to the internal 4200 Model# and UPC. Review volume, sentiment, and theme breakdowns are then calculable at the Model# level, not scattered across six ASIN silos.