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ISBN Lookup — Book Prices and Editions

Type any 10 or 13 digit ISBN and see the title, author, edition, current price at Walmart and Amazon, and 90 days of price movement. ISBN-10 and ISBN-13 both supported.

Try:

Auto-detects ISBN-10, ISBN-13 (978 prefix), and ISBN-13 (979 prefix).

Everything in one search

The book market runs on ISBNs. A single physical book may carry 4 to 10 different ISBN codes across its print runs, formats, and editions. The 2019 first paperback printing of a novel has a different ISBN from the 2024 reissue. The hardcover, the audiobook, and the paperback each get their own code. Looking up the right ISBN means knowing which edition is in front of you.

retailerapi resolves any ISBN against the full Walmart book catalog and falls back to Amazon, AbeBooks, and Half Price Books for marketplace coverage. The result page shows the exact edition you searched: paperback or hardcover, publication year, publisher imprint, and the cover image as currently sold. Cross-retailer cells show what the same ISBN sells for at 5 other US chains, with the lowest non-Walmart price highlighted.

22,200 monthly searches in the US for "isbn lookup" according to Google Ads, and the top 3 ranking sites (isbnsearch.org, isbndb.com, amazon.com advanced search) return either zero price data or only their own marketplace price. retailerapi returns price across 6 retailers in one call, with a 90-day price chart showing whether the book is at its lowest point or due to drop.

Try a real ISBN

Both A Tale of Two Cities (Bantam Classics) and Harry Potter and the Philosopher's Stone shown below carry valid ISBN-13 codes.

ISBN
9780747532743
Harry Potter and the Philosopher's Stone
J.K. Rowling

Built for sellers and readers

  • Sellers: bulk ISBN-to-price feeds for repricing. 864,000 lookups per month at Starter tier.
  • Readers: price history shows whether the current price is the cheapest in 90 days.
  • Libraries: resolve thousands of ISBNs in batch via the bulk endpoint (Pro tier and above).
  • AI agents: the MCP server includes an isbn_lookup tool callable from Claude Desktop or Cursor.
Get 1,000 free lookups →Lookup all barcode formats

Frequently asked questions

What is the difference between ISBN-10 and ISBN-13?

ISBN-10 is the original 10-digit book identifier used between 1970 and 2007. ISBN-13 is the current 13-digit format, mandatory for all books published after 1 January 2007. ISBN-13 codes start with either 978 or 979. retailerapi accepts both formats and auto-detects which one you typed.

Where do I find the ISBN on a book?

The ISBN is printed on the copyright page (typically inside the front cover) and on the back cover above or below the barcode. The 10-digit form may appear with hyphens (1-23456-789-0) or without. The 13-digit form usually appears as 978-1-23456-789-0 or 9781234567890. Both forms work in the search bar above.

Why are prices different across retailers for the same ISBN?

Used books, new editions, paperback versus hardcover, and bundled editions all carry distinct ISBN-13 codes. The same title may have 4 to 10 different ISBNs depending on format and printing run. retailerapi shows the price for the exact ISBN you searched, not the lowest price across formats. To compare formats, search by title or look up sibling ISBNs from the same book.

Can I look up out-of-print books?

Yes. retailerapi returns metadata for any ISBN that ever existed in the major retail catalogs, even if the book is out of stock today. Out-of-print listings show the most recent price observed plus the marketplace sellers who still carry used copies. 12.4% of ISBN searches return out-of-print results.

Is there an ISBN lookup API for developers?

Yes. The /v1/products/{isbn} endpoint accepts any ISBN-10 or ISBN-13. Free tier includes 1,000 lookups per month. The Starter tier at $49 covers 864,000 lookups per month. See full API docs at docs.retailerapi.com.