What it means
The barcode on a book is its ISBN in machine-readable form. Since 2007 the ISBN is itself an EAN-13 number (beginning 978 or 979), so the bars are a standard EAN-13 symbol — historically called a Bookland barcode — with the ISBN printed in human-readable digits above it. Many carry a second, smaller five-digit add-on: 5 followed by the US price in cents, so 51999 means $19.99; 90000 means no price is encoded.
Placement and reproduction are standardised because scanners are fussy. The barcode sits at the lower right of the back cover (or the back of a jacket), printed in solid black on white or a pale background, at 80–100% of nominal size, with a clear quiet zone on both sides and no lamination gloss that scatters the laser.
Retailers and distributors require it; a book sold only from an author's own site does not need one. Barcode generators are free once you have the ISBN.
In Bindery
Bindery’s bookstore pack adds a barcode to the wrap cover, alongside clean files ready for Amazon KDP, IngramSpark, Apple Books and Kobo.
Make the book, not the checklist
Describe a book or upload a manuscript. Bindery writes with you, typesets in LaTeX, sizes the spine from the real page count and produces printer-validated files — the watermarked proof is always free.
Start Free