BookCrossing BCID Generator

A BCID (BookCrossing ID) is a unique identifier assigned to each book registered on BookCrossing.com. It allows anyone who finds a released book to look it up, see its journey history, and log where they found it. Each BCID includes a built-in checksum digit to help detect typing errors when entering the ID.

The standard BCID format is PPP-NNNNNNNC — a 3-digit prefix, followed by a hyphen, then 8 digits where the last digit is the checksum. This gives a total of 11 digits. Example: 123-45678905 where 5 is the calculated check digit. The hyphen is optional for validation purposes; our tool accepts both formats.

Our checksum algorithm uses alternating weights (1 and 3) on the first 10 digits, similar to the EAN / ISBN-13 check digit method:

1. Take the 10 digits (3 prefix + 7 identifier).
2. Multiply each digit by alternating weights: 1, 3, 1, 3, 1, 3, 1, 3, 1, 3.
3. Sum all the products.
4. Check digit = (10 − (sum mod 10)) mod 10.

This detects single-digit errors and most transposition errors, making BCIDs more robust.

This tool generates BCIDs that follow the same format and checksum rules used by BookCrossing. However, to officially register a book and have it tracked in the BookCrossing database, you need to use BookCrossing.com directly. Our generator is useful for testing, development, mock data, educational purposes, or understanding how BCID checksums work.

Common use cases include:

• Developers building BookCrossing-related apps who need test data.
• Educators teaching checksum algorithms and data validation concepts.
• BookCrossing enthusiasts who want to understand ID structure.
• Event organizers pre-generating IDs for book-tracking activities.
• QA/testing scenarios requiring valid-format BCIDs.

Within each bulk batch, we guarantee all generated BCIDs are unique (no duplicates). However, since there is no central registry, a BCID generated here could theoretically match one generated elsewhere. The address space of 10¹⁰ possible combinations (10 billion) makes accidental collisions extremely unlikely for most practical purposes.

An ISBN (International Standard Book Number) identifies a specific edition of a published book globally. A BCID identifies a specific physical copy of a book within the BookCrossing system. Multiple copies of the same book (same ISBN) will each have their own unique BCID, allowing individual tracking of each copy's journey.