Barcode size and quiet zones: how small can you print?

For retail EAN-13 and UPC-A barcodes, the usual range is 80% to 200% of the nominal size, so you can print somewhat smaller than standard but not much. Whatever the format, keep the blank margins either side of the barcode, called quiet zones, and do not cut the bars shorter than the format allows. The details below explain the limits and how to check them before a print run.

The X-dimension: the measure behind barcode size

Every linear barcode is built from narrow and wide bars and spaces. The width of the narrowest bar is called the X-dimension, and each of these narrowest units is called a module. All other measurements, including the quiet zones, are multiples of it.

A smaller X-dimension means a more compact barcode, but it also makes the code harder to print cleanly and harder to scan.

Nominal size for EAN and UPC

EAN-13 and UPC-A, the barcodes used on retail products, have a defined nominal size, also called 100% magnification. At 100%, the X-dimension is 0.33 mm. An EAN-13 symbol at this size measures about 37.29 mm wide by 25.93 mm high, including the quiet zones and the printed digits underneath. The bars themselves are 22.85 mm tall.

Retail barcodes can usually be printed between 80% and 200% of nominal size. At 80%, an EAN-13 is roughly 29.8 mm wide; at 200%, roughly 74.6 mm. The lower end leaves less room for print quality problems. If you have space, printing at 100% or a little above is the safer choice. Some retailers and logistics partners set their own minimum sizes, so check any requirements you have been given.

Other formats, such as Code 128, Code 39 and ITF, do not have a single nominal size in the same way. The width depends on the X-dimension you choose and how many characters you encode. Longer data produces a wider barcode.

Quiet zones

A quiet zone is the blank, unprinted margin on each side of a barcode. The scanner uses it to recognise where the code begins and ends. If text, a border, a fold or the edge of a label intrudes into it, the barcode may fail to scan even though the bars themselves are perfect.

Quiet zones are measured in modules, so they grow and shrink with the barcode:

EAN-13 needs at least 11 modules on the left and 7 on the right. At nominal size that is about 3.63 mm on the left and 2.31 mm on the right.
UPC-A needs at least 9 modules on each side.
Most other linear formats, including Code 128 and Code 39, need a quiet zone of around 10 times the narrowest bar on each side.

On a label, keep the quiet zone clear of edges and text, and add a little extra in case labels print slightly out of line.

Shortened bars

To save space, some packaging shortens the bars of a barcode, a practice known as truncation. This keeps the width the same but reduces the height. It may still scan with a handheld scanner, but it is much harder to read at a checkout.

Retail checkout scanners are designed to read a barcode passed across them at different angles. Tall bars give the scanner more chances to catch the full code in one sweep. When the bars are cut short, a barcode often needs to be lined up precisely, which slows down the queue and leads to manual entry. For this reason, many retailers discourage or reject truncated EAN and UPC barcodes. Keep the full bar height wherever you can.

Printer resolution

A printer builds every bar from tiny dots. Common resolutions are 203 dpi and 300 dpi for thermal label printers, and 600 dpi for many office laser printers. At 300 dpi each dot is about 0.085 mm wide; at 600 dpi, about 0.042 mm.

For the cleanest result, the narrowest bar should be a whole number of printer dots. If it falls between dot widths, the printer rounds some bars up and others down, and the bar widths become uneven, which can cause scanning errors. For example, 0.33 mm is not a whole number of dots at 300 dpi, but 4 dots (about 0.34 mm) is very close and prints evenly. Many label printing tools adjust the X-dimension slightly for this reason. When you have a choice, pick a size where the narrowest bar lines up with the printer’s dots, and print at actual size so the PDF is not rescaled on the way to the printer.

Colours that scan

Most barcode scanners read the contrast between bars and spaces using red light. That has a practical effect on colour choice:

Use dark bars on a light background. Black on white is the most reliable. Dark blue, dark green and dark brown bars usually also work on white.
Avoid red, orange and yellow bars. Under red light, these colours reflect almost as much light as the white background, so many scanners cannot see them at all.
Avoid light bars on a dark background for retail barcodes, as many scanners expect dark bars on a light background.
Avoid shiny or metallic inks and backgrounds, which can reflect light unpredictably.
Watch for low contrast, such as grey bars on a pale background, or printing directly on brown cardboard.

Test before a print run

Before printing labels or packaging in quantity, print a sample at the final size, on the final material, using the same printer and settings. Then:

Measure the barcode width with a ruler and compare it with the size you intended.
Check that the quiet zones are clear on both sides.
Scan it with the kind of scanner it will meet in use, such as a checkout scanner, a warehouse handheld or a phone app.
Confirm that the scanned digits match exactly, including any check digit and leading zeros.

A sample that scans well on one device is a good sign, but it does not prove that every scanner will read it. For retail products, it is worth asking your retailer or distributor whether they have any specific requirements.

You can create barcodes in the Barcode Generator and place them on labels at the size you need in the Label Maker. For help getting the print size right, see How to print labels at actual size.