ISBN-13

What is an ISBN-13 barcode?

ISBN-13 (International Standard Book Number, 13-digit) is the barcode printed on the back cover of virtually every book published since 2007. Structurally, an ISBN-13 barcode is an EAN-13 barcode: the ISBN-13 number is a valid EAN-13 beginning with the GS1 prefix '978' (Bookland) or '979'. The ISBN itself is administered by the International ISBN Agency and assigned through national ISBN agencies worldwide. The barcode is simply an EAN-13 representation of the ISBN-13 number and is scanned identically by all retail point-of-sale and library systems.

The 13 digits explained

An ISBN-13 has the following structure:

• Digits 1–3: GS1 prefix — always 978 (Bookland) or 979.
• Digits 4–6: Registration group (language/country — e.g., 0 or 1 for English).
• Digits 7–11: Publisher prefix (assigned by the national ISBN agency).
• Digits 12: Title number (assigned by the publisher).
• Digit 13: Modulo 10 check digit (same algorithm as EAN-13).

The 'ISBN-13' number printed on the book (e.g., ISBN 978-0-306-40615-7) is the same 13-digit number encoded in the barcode.

Check digit (identical to EAN-13 Modulo 10)

The ISBN-13 check digit uses the exact same Modulo 10 algorithm as EAN-13:

1. Multiply odd-position digits (1,3,5,7,9,11) by 1.
2. Multiply even-position digits (2,4,6,8,10,12) by 3.
3. Sum all products.
4. Check digit = (10 − (sum mod 10)) mod 10.

Note: The older ISBN-10 used a different Modulo 11 check digit and is no longer used on barcodes.

The 5-digit price add-on (EAN-5)

Many books carry a second, smaller barcode to the right of the main ISBN-13 barcode. This is an EAN-5 (5-digit) add-on encoding the suggested retail price:

• US: '5' followed by the price in cents (e.g., 51995 = USD 19.95).
• Canada: '6' followed by the price in Canadian cents.
• '90000' means 'no price' or 'see retailer'.

The add-on is optional and is printed separately from the main ISBN-13 barcode.

ISBN-13 vs. EAN-13 vs. ISBN-10

ISBN-13 is technically an EAN-13 with a 978/979 prefix — there is no physical difference between an ISBN-13 barcode and a standard EAN-13 barcode. ISBN-10 (9 digits + Modulo 11 check) was the predecessor format, discontinued for new barcodes in 2007. All ISBN-10 numbers were converted to ISBN-13 by prepending '978'. Any EAN-13 scanner reads ISBN-13 natively.

When to use ISBN-13

Use ISBN-13 on any book, journal issue, or printed publication that will be sold in retail channels. Obtain your ISBN-13 from your national ISBN agency (e.g., Bowker in the US, Nielsen in the UK) — do not invent ISBN numbers. Self-published authors must also obtain a valid ISBN from their national agency if they wish to sell through retail channels.

Printing requirements

ISBN-13 follows the same GS1/EAN-13 printing specifications: nominal size 37.29 mm × 26.26 mm, magnification 80%–200%, quiet zone 11× module width left and 7× right. The human-readable number should be printed with 'ISBN' prefix and hyphens (e.g., ISBN 978-0-306-40615-7) above or below the barcode per publisher convention.

Common scanning failures

ISBN-13 barcodes on books typically fail due to low-contrast printing on coloured or textured back covers, cropping of quiet zones by cover artwork, or damage to the barcode from handling. Always place the barcode on a white or light-coloured panel with clear quiet zones, separate from background artwork.