---
title: "What Is an ASIN? Amazon's Book Identifier"
description: "What an ASIN is, how it differs from an ISBN, where to find your book's ASIN, and why the Kindle and paperback editions each have their own."
url: "https://www.superebook.ai/glossary/asin"
updated: "2026-10-20"
---

# ASIN

**Definition.** An ASIN (Amazon Standard Identification Number) is the 10-character code Amazon assigns to every product in its catalog. Each edition of a book sold on Amazon has its own, the Kindle ebook and the paperback alike. It identifies the product only inside Amazon: unlike an ISBN, it means nothing to other bookstores or library catalogs.

Sources checked October 20, 2026.

## How it works

Amazon creates an ASIN whenever a new product detail page is made, so publishing an ebook on KDP gives it one without your asking. You can read it in two places: in the page address, after /dp/, and in the product details section of the page. Because a Kindle ebook needs no ISBN on KDP, its ASIN is often the only identifier it has. ASINs matter for reviews too: KDP says customer reviews are shared across marketplaces only where the same book's ASIN and format are live.

## An example

You run an ad for the Kindle edition and link to its page. The link should carry the ebook's ASIN after /dp/; the paperback's page has a different code, since every product gets a unique one, so a link built from the paperback's address sends readers to the print edition instead.

## Common mistakes

Giving an ASIN where another retailer or a library asks for an ISBN: outside Amazon it identifies nothing. Assuming the ebook and paperback share one code. And buying an ISBN for a Kindle ebook only to get it listed: KDP says an ISBN is optional for ebooks, and Amazon assigns the ASIN either way.

## Questions

**Do I need to buy an ASIN for my book?** No. Amazon assigns one to every product detail page, including your Kindle ebook and your paperback, at no cost.

**Where do I find my book's ASIN?** On the book's Amazon page: in the address after /dp/, and in the product details section further down the page.

## Sources

- [Amazon: Understanding ASINs (Sell on Amazon)](https://sell.amazon.com/blog/what-is-an-asin): What ASIN stands for, its 10 characters, assignment to every product detail page, and where to find it.
- [KDP: What is an ISBN and Imprint?](https://kdp.amazon.com/en_US/help/topic/G201834170): ISBNs optional for ebooks and low-content books.
- [KDP: Customer Reviews](https://kdp.amazon.com/en_US/help/topic/G202101910): Reviews shared across marketplaces only where the same ASIN and format are live.

## Related terms

- [ISBN](https://www.superebook.ai/glossary/isbn.md)
- [KDP (Kindle Direct Publishing)](https://www.superebook.ai/glossary/kdp.md)
- [Low-content book](https://www.superebook.ai/glossary/low-content-book.md)

## Read next

- [Do you need an ISBN for an ebook on KDP?](https://www.superebook.ai/guides/do-you-need-an-isbn-for-an-ebook.md)
- [How to write a KDP book description](https://www.superebook.ai/guides/how-to-write-a-kdp-book-description.md)
- [A 30-day ebook launch checklist](https://www.superebook.ai/blog/ebook-launch-checklist.md)
- [All glossary terms](https://www.superebook.ai/glossary.md)