Fewer choices than you would expect. Red, orange and yellow are out as bar colours, and the size comes from a magnification percentage, not from a millimetre you pick: counted from the GS1 UK size table, EAN-13 runs from 80 to 150 percent, and 100 percent is 37,29 mm wide. That table is the reason a barcode can decide how wide your smallest pack is.
Colours that cannot be bars
Red, orange and yellow cannot be used as bar colours. That is a rule, not a preference, and no amount of art direction changes it.
What this costs you is a decision you may not have expected to make: if your brand colour is one of those three, the barcode is where it does not go. Put it somewhere the code does not need it, and keep the bars in a colour that reads as dark against a light background. MarkaWorks checks this against the palette before a range goes to artwork, because it is cheaper than discovering it on a proof.
Height, and why trimming it is the wrong saving
GS1 UK puts it in one sentence: “The height of the barcode should not be reduced (truncated) unless absolutely necessary as this makes it more difficult to scan.” Our own production record is stricter still and treats height reduction as a zero tolerance item.
Either way the instruction to your designer is the same. Treat the height as fixed at the start. A pack that needs the code shortened is a pack that needs a different layout, and finding that out at artwork stage is cheaper than finding it out at the till.
Magnification, not millimetres
Magnification is the part that surprises founders. A retail barcode is not sized in millimetres you choose; it is sized by a magnification percentage, and the percentage carries the millimetres with it.
| Magnification | X-dimension | Width | Height |
|---|---|---|---|
| 80 percent | 0,330 mm at nominal | 29,83 mm | 18,28 mm |
| 100 percent | 0,330 mm | 37,29 mm | 22,85 mm |
| 150 percent | 0,495 mm | 55,94 mm | 34,28 mm |
The figures in the table are from the GS1 UK point of sale table, read on 13 September 2026. Use them in this order.
- Take the second row, 100 percent, as your working assumption.
- Take the first row, 80 percent, as your floor, and go below it only where the printing method allows it.
- Check what a 29,83 mm block does to the smallest pack in your range, before the dieline is drawn.
The sequence runs backwards from how it feels: the code has a floor, the floor has a width, and the width constrains the pack. Settle it before the dieline rather than after.
Substrates that change the job
Metallised and transparent materials need special technique for the barcode. A code printed straight onto foil or onto clear film is not the same job as a code printed onto white carton.
If your smallest variant is a sachet and your largest is a carton, you are running two different barcode problems inside one range. Ask the question per material, not per brand.
What the layout has to allow for
On flexo, the anilox and the bar width reduction determine barcode quality. Those are press settings, decided by your printer, not by your designer, and they are the reason two identical files can scan differently from two presses.
These are production decisions rather than layout decisions, so the barcode is settled before the artwork is final. Name the process before the file is finalised.
What to settle before the dieline
| Decision | Who answers it | What it changes |
|---|---|---|
| Bar colour | You, from the palette | Removes red, orange and yellow as options |
| Height | Fixed, no trimming | The panel has to accommodate it |
| Magnification ratio | Standard plus your printer | Sets the minimum width of the smallest pack |
| Substrate | You, per variant | Metallised and clear need a different approach |
| Production settings | Your printer | Determines whether the printed code scans |
Every row above is answerable before anyone opens a design file, and each one that is left open becomes a redraw later.
Where our record stops
The table above is the EAN-13 point of sale case. Other symbologies and other markets carry their own figures, and a sachet printed on demand is not governed by the same minimum as a carton printed offset.
So take the percentage and the resulting millimetres from the specification that applies to your symbology, then have your printer confirm both for the process and the material you are actually using. MarkaWorks settles barcode position and size in the structural stage of a packaging project, before the front panel is designed, because it is the one element on the pack whose size is not a design decision.
The barcode in a MarkaWorks project
MarkaWorks settles barcode position and size in the structural stage, before the front panel is designed, and checks the bar colour against your palette before a range goes to artwork. We ask the question per material, because a sachet and a carton are two different barcode jobs. The structural stage is described on the packaging and product design page.
Working on a new range? Reach the MarkaWorks team through the contact page.
Quick answers on barcode colour and size
Can a barcode be red or yellow?
No. Red, orange and yellow cannot be used as bar colours, and no amount of art direction changes that. If your brand colour is one of those three, keep it elsewhere on the pack and set the bars in a colour that reads as dark against a light background.
How is the size of a barcode decided?
By a magnification percentage, not by a millimetre you pick. Counted from the GS1 UK size table, EAN-13 runs from 80 to 150 percent, and 100 percent is 37,29 mm wide. The percentage carries the width and height with it.
Should I shorten a barcode to fit a small pack?
No. GS1 UK says the height should not be reduced unless absolutely necessary, because it makes the code harder to scan, and our production record treats height reduction as zero tolerance. A pack that needs a shorter code needs a different layout.
Does the printing method change how a barcode scans?
Yes. On flexo, the anilox and the bar width reduction determine barcode quality, and those are press settings your printer decides. That is why two identical files can scan differently from two presses, and why the process is named before the file is final.
Three colours are out as bars, height has no tolerance at all, and the size is set by a ratio rather than by a millimetre. What that costs you on the pack.
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