Barcode label size and placement: how big, and where it goes

Print the barcode at least 30 mm wide by 21 mm tall with a clear margin of about 4 mm on the left and 3 mm on the right. Put it on one flat face, low on the back of the pack, where the till scanner lands.

Start from the scanner, not the label

A retail barcode has one job. It scans at a till. Everything about barcode label size and placement follows from that. The scanner at a counter reads a strip of light and dark bars. It needs the bars wide enough to tell apart, tall enough to catch the beam at an angle, and clear of anything printed next to them.

This post does one task. By the end you will have a label size in millimetres, a clear margin written down, and a spot on your pack marked for the label. Take a ruler, your pack or a sample of it, and a pen.

The size that scans

A standard retail barcode on a shelf product is printed at a nominal size of about 37 mm wide and 26 mm tall. That measurement includes the clear margin on each side, which is covered in the next section. The bars alone take up a little under 32 mm of the width.

Printers and designers scale this up or down. The safe range runs from 80 percent to 200 percent of the nominal size. At 80 percent the label is close to 30 mm wide and 21 mm tall. That is the smallest print most counter scanners read without a second pass. Below it, the narrowest bar gets thinner than the ink spread of an ordinary label printer, and the gaps start to close.

Going larger is rarely a problem for scanning. A barcode at 150 percent is about 56 mm wide and 39 mm tall. It reads from further away and at steeper angles. The cost is space on the pack. For a small jar or a sachet, 100 percent is the usual compromise.

Height matters more than people expect. Shortening the bars to squeeze a label onto a slim box is called truncation. A scanner held at an angle sweeps a diagonal line across the code. If the bars are too short, that line runs off the top or bottom before it crosses every bar. Keep the bars at least 18 mm tall. If you must trim, cut height before width, and never below 15 mm.

Write down two figures: the width of your barcode including margins, and the height of the bars. For most shop products that is 37 mm by 26 mm.

The quiet zone

The quiet zone is the blank strip of label on the left and right of the bars. Nothing is printed there. Not a border, not a line of text, not the edge of a photograph. The scanner uses it to find where the code starts and stops. If a design element sits inside it, the till reads a shorter code or none at all.

At the nominal size, the quiet zone on the left is about 3.6 mm and on the right about 2.3 mm. The left one is wider because the scanner needs more room to lock on. A simple rule covers both: leave a clear 4 mm on the left and 3 mm on the right. If you scale the barcode up, scale these margins with it.

The quiet zone has to be the same colour as the spaces between the bars. On a white label that means white. On a coloured pack, the whole barcode block including the margins should sit on a white or very pale panel. Red, orange and yellow backgrounds read as white to most scanners and work. Dark backgrounds do not. Black bars on white is the combination that scans every time. Dark blue or dark green bars on white also read well. Avoid red bars, metallic ink and bars printed on a reflective foil.

Mark the quiet zone on your layout as a box around the bars. Designers often shave it to fit a logo. Tell them the box is part of the barcode, not spare space.

Where the label goes on the pack

Most tills in India have a handheld scanner, not a flatbed. The cashier picks the product up, turns it, and aims. A few supermarkets have a fixed scanner under glass, where the product slides across. The barcode has to work for both.

Put the barcode on one flat face, with the bars running vertically and the code reading left to right along the base. On a box, the back face low down, towards the right as the cashier holds it, is the usual spot. On a bottle or a can, place it on the back label with the bars running up and down the height of the container, so the code reads around the curve. Bars that stand upright on a curve each stay flat to the beam. Bars laid along the curve bend, and the gaps at the edges stretch.

Keep the barcode at least 8 mm from any edge, fold or seam. On a flexible pouch, place it on the flat body, never across a gusset or a seal. Do not put it on a jar lid. Lids come off, and a code on a curved lid rarely reads.

Avoid the natural bottom of the pack. A product standing on a shelf hides it, and a cashier has to flip a heavy item to find it. Avoid the top too, where tape and price stickers land. The lower third of the back face is where a cashier looks first and where the scanner reaches without turning the product more than once.

If your product ships in a carton of six or twelve, the outer carton needs its own code and its own label. Place the carton label on the long side, not the top, so a worker can scan it on a pallet without lifting it.

Paper, print and the test at a till

A barcode scans as well as its print. For a label printer in a shop, use a direct thermal or thermal transfer roll of at least 50 mm width and print at the printer's full resolution. Direct thermal labels fade under heat and sunlight within months, so for a product with a long shelf life use thermal transfer with a wax resin ribbon. For a pack printed at a press, ask the printer for a bar width reduction so the ink spread does not fatten the bars.

Glossy laminate over the barcode causes glare. A matte varnish is fine. If the pack is wrapped in clear film, keep the film flat over the barcode and make sure no seam crosses it.

Before you print a thousand labels, print ten. Stick one on the pack where you marked it. Take it to a shop with a till and ask the cashier to scan it, or use a phone with a barcode scanner app held at arm's length. Try it straight on, then at a tilt, then with the pack turned a quarter. If it reads at the first pass each time, the size and the spot are right. If it fails only at a tilt, the bars are too short. If it fails straight on, look for ink spread or something sitting in the quiet zone.

Getting the number onto the label

The label needs a number to encode. You can buy a retail barcode number from https://purchasebarcode.com/ and receive the digits along with a print-ready image of the bars. Download the image at the size you worked out above. Do not stretch or squash it in a layout program. Use the scaling control, which keeps every bar in proportion. Keep the human-readable digits under the bars, in a plain font, so a cashier can key them in if a label gets scuffed.

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If a store asks you about numbers before it lists your product, tell us where you sell and we will set you up with the right type for that counter. Once the labels are printed and the first ten scan clean at a till, the task is done.