Print quality: 100% K, vector, size
ISBN barcode size: magnification, minimum and quiet zones
Short answer
An EAN-13 (and so an ISBN barcode) is sized by magnification. At 100% the narrowest bar, the X-dimension, is 0.330 mm. GS1 allows 80% (0.264 mm) to 200% (0.660 mm). The US book guidelines describe the 100% symbol as about 1 in high, and they also allow 80% to 200%. KDP suggests a 2 x 1.2 in box with a 1.4 x 0.8 in minimum. Never go below 80%, never stretch it in one direction only, and keep the quiet zones empty.
What "magnification" means
A barcode has a fixed number of modules (narrow units). An EAN-13 is 95 modules from the first bar to the last. Making it bigger or smaller only changes how wide one module is. That width is the X-dimension.
| Magnification | X-dimension (narrowest bar) |
|---|---|
| 80% (minimum) | 0.264 mm |
| 100% (nominal) | 0.330 mm |
| 200% (maximum) | 0.660 mm |
GS1 also gives the bar height for each magnification, so height and width scale together. That is the point: scale the barcode proportionally, never in one direction only.
Quiet zones
The quiet zones are the empty spaces left and right of the bars. A scanner uses them to find where the barcode starts and ends.
- EAN-13: at least 11 modules on the left and 7 modules on the right.
- At 100%, 11 modules is about 3.6 mm and 7 modules about 2.3 mm.
- The US book guidelines mark the right-hand quiet zone with a ">" sign in the human-readable line, so nobody prints into it.
Nothing goes into the quiet zones: no text, no frame, no edge of a colored panel.
How big should a book barcode be?
| Context | Size guidance |
|---|---|
| GS1 EAN-13 | 80% to 200% of nominal |
| US book trade (BISG) | With the add-on: 1 x 2-3/16 in (about 2.19 in wide) at 100%, about 1-3/4 in wide at 80%; 80% to 200% allowed |
| Amazon KDP | Suggested box 2 x 1.2 in; minimum 1.4 x 0.8 in |
| IngramSpark | 1.75 x 1 in recommended, large enough to scan |
In practice, a book barcode at 80% to 100% fits every common back cover. Going larger does not improve scanning on a book; it only takes more space.
Truncation: making it shorter
Designers often want a shorter barcode. Cutting the height (truncation) makes the barcode less tolerant of a scanner held at an angle, and GS1 gives a minimum height for each magnification for that reason. On a book cover there is usually no reason to truncate: use 80% to 100% at full height, or a layout made for the platform's box.
Common size mistakes
- Scaling below 80% to fit a busy back cover.
- Stretching only the width to fill a box. The module widths become uneven to the standard and scanning gets unreliable.
- Cropping the quiet zones by drawing a white box that is too tight.
- Scaling a raster barcode up, which makes the edges soft.
The sizes Barcode Rocket uses
- ISBN and ISBN + price: 100% (X-dimension 0.33 mm); the files are about 1.72 x 1.2 in and 2.37 x 1.2 in, white margins included.
- Amazon KDP: a 2.0 x 1.2 in box with the barcode at 88%.
- IngramSpark: 80%, about 1.26 x 1.0 in, so it fits IngramSpark's 1.75 x 1 in area.
Place every file at 100% in your layout program. The size is already correct.
Frequently asked questions
What is the minimum size of an ISBN barcode?
80% magnification, which means a 0.264 mm narrowest bar. For KDP, the minimum box is 1.4 x 0.8 in.
Can I make the barcode smaller than 80% if my printer is good?
The standards do not allow it, and the risk is at the till, not at the printer. Do not go below 80%.
Can a barcode be too big?
Up to 200% is allowed. On a book cover there is rarely a reason to go above 100%.
Why is the KDP box bigger than the barcode?
The 2 x 1.2 in box includes white space around the barcode, the quiet zones and the ISBN line on top.
Sources
- GS1 General Specifications (EAN-13 X-dimension range, heights, quiet zones): ref.gs1.org/standards/genspecs
- GS1 UK, How big should a point of sale barcode be?: gs1uk.org
- Book Industry Study Group, Barcoding Guidelines for the US Book Industry (1 in high at 100%, 80% to 200%, quiet zone marker): bisg.org
- Amazon KDP Help, Barcodes (2 x 1.2 in suggested, 1.4 x 0.8 in minimum): kdp.amazon.com
- IngramSpark, Understanding IngramSpark Title Processing (1.75 x 1 in): ingramspark.com
- ISO/IEC 15420, EAN/UPC bar code symbology specification: iso.org/standard/46143