Module widths and heights
| Code | Module X | Bar height | Quiet zone |
|---|---|---|---|
| UPC-A, EAN-13 | 0.264–0.660 mm (80–200%), 0.33 nominal | 22.85 mm at 100%, scales with X | UPC 9X each side; EAN 11X left, 7X right |
| UPC-E | 0.264–0.660 mm | 22.85 mm at 100% | 9X left, 7X right |
| EAN-8 | 0.264–0.660 mm | 18.23 mm at 100% | 7X each side |
| ITF-14 | 0.495–1.016 mm | about 32 mm (1.25 in) | 10X inside bearer bars |
| GS1-128 (logistics) | 0.495–1.016 mm | 31.75 mm | 10X each side |
| Code 128, Code 39 | 0.19 mm and up (0.25 mm for phones) | 6.35 mm or 15% of the width | 10X each side |
| QR code | 0.25 mm and up | square | 4X all round |
| Data Matrix | 0.25 mm and up | square | 1X all round |
| PDF417 | 0.19 mm and up | rows 3X tall | 2X all round |
Why quiet zones matter
A scanner finds a linear barcode by the blank space before the first bar. Text, a box edge or a fold within the quiet zone makes the scanner miss the start, which is the most common reason a correctly printed barcode will not read. The generators on this site never make the quiet zone smaller than the minimum.
Truncating height
Cutting the bar height of a UPC or EAN (truncation) keeps the code readable for a handheld scanner, but fixed scanners at checkouts read best from any angle when the bars keep their full height. GS1 discourages truncation on retail items.
Questions
- What is the smallest UPC I can print?
- 80% magnification: a 0.264 mm module, 29.83 mm wide with quiet zones. Below that, the code is outside the specification.
- How big should a QR code be on a box?
- About one tenth of the scanning distance: 25 mm wide for 25 cm away, including its white border.