Authors buy ISBNs and are then offered barcodes for an additional fee, which leaves many thinking the barcode is somehow part of the ISBN purchase. It is not. The barcode is a picture of the number, and anyone can draw it.
What is on the back of a book
The barcode on a book is an EAN-13 symbol, the same family of barcode used on groceries. Book barcodes are sometimes called "Bookland EAN" because the 978 and 979 prefixes were reserved for books as if they were a country.
The 13 digits under the bars are the ISBN itself. The line of text above the bars, usually "ISBN 978-1-…", is the same number with hyphens for human readers. A register scans the bars, reads the ISBN, and looks the book up.
The five extra digits
Many book barcodes have a smaller, second barcode to the right with five digits. This is the price add-on (EAN-5). The first digit is the currency, the other four are the price:
5followed by1699means US $16.994means New Zealand dollars,3Australian,6Canadian0or1means pounds sterling90000means "no price specified"
US bookstores expect the price add-on. It is why a US cover price often appears twice, once in print and once encoded. If your price changes, the add-on is wrong until you reprint, which is one reason some publishers print 90000 and let the retailer set the price.
Why you do not need to buy one
A barcode is generated from the ISBN by a deterministic algorithm. There is no registry to enter, no licence to hold. The same ISBN always produces the same bars.
Your cover designer may generate one, free online tools generate them, and ScanSpine generates one for every title with an ISBN as part of the record: a vector SVG for the cover and a high-resolution PNG, with the price add-on computed from the list price you entered.
What makes a barcode scan
- Size. The standard EAN-13 is about 37 mm wide at 100%. You can shrink to roughly 80% before scanners start to struggle. Do not squash it horizontally.
- Quiet zone. Leave clear space either side of the bars. The light margin is part of the symbol.
- Contrast. Black bars on white is the safe choice. Dark bars on a light cream are fine. Red bars on anything are not, because most scanners use red light and cannot see them.
- No gloss over the bars if you can avoid it. A matte varnish or an uncoated patch helps.
- Test it. Scan the printed proof with a phone app and, ideally, a real retail scanner.
A barcode without an ISBN
If your book has no ISBN, you cannot have an EAN-13 book barcode: there is no number to encode. Some services will draw a 978 symbol around a made-up number. Do not use one: it can collide with a real book at a register and will cause a bookstore nothing but trouble.
ScanSpine never does this. A title without an ISBN gets a Code 128 barcode of its ScanSpine identifier, useful for your own inventory and events, and a QR code that works everywhere a phone can see it. When you add an ISBN later, the barcode switches to the official format.