// Key takeaways
- EAN-13 carries a GTIN-13 only: no batch, date or serial number.
- At the target size the symbol is 37.29 mm wide including quiet zones and 22.85 mm high; GS1 allows X-dimensions from 0.264 to 0.660 mm for till-only items.
- GS1 prefers the lower right of the back panel, 8 to 100 mm from an edge, and limits picket-fence codes on small round containers.
- Because the code is part of the artwork, a line check compares the GTIN read with the product the line is running.
- Reading the code on the line is not the print grade a retailer or GS1 South Africa measures.
What does an EAN-13 barcode carry?
An EAN-13 barcode carries a GTIN-13, the Global Trade Item Number of the consumer unit (GS1 General Specifications). GS1 South Africa describes EAN and UPC as the most popular GS1 barcodes, printed on nearly every consumer product (GS1 South Africa, barcode types). The barcode says what the product is; it says nothing about the batch, the date or which individual pack it is. Those go in the printed date and lot code, or in a 2D code (chapters 4 and 5).
The symbol is built from a left quiet zone, a guard pattern, six characters, a centre guard, six more characters and a right guard and quiet zone. Twelve characters carry thirteen digits: the first digit has no bars of its own and is encoded by the mix of number sets used in the left half (GS1 General Specifications, 5.2.2.1).
Swipe sideways to see the whole drawing →
Worked example: the check digit. The last digit is calculated from the other twelve, so a reader can reject most misreads. GS1’s example number 061414112345 is weighted 1, 3, 1, 3 … from the left: 0 + 18 + 1 + 12 + 1 + 12 + 1 + 3 + 2 + 9 + 4 + 15 = 78. The next multiple of ten is 80, so the check digit is 2 and the GTIN-13 is 0614141123452 (GS1 General Specifications, 7.9.1). A check digit catches a misread digit; it does not catch a correctly printed number that belongs to another product.
Where does it go, and who decides the number?
EAN-13 goes on the consumer unit that is scanned at the till. The brand owner allocates the GTIN from its GS1 company prefix, and the artwork carries the barcode. Groupings of consumer units that are not meant for till scanning, such as an outer case, use other symbols (chapter 2).
For new packaging GS1 prefers the lower right quadrant of the back panel, with the alternative the lower right of another panel. The barcode should be no closer than 8 mm and no farther than 100 mm from the nearest edge, because cashiers hold packs by their edges. Bags take the barcode in the centre of the back, about a third up from the bottom (GS1 General Specifications, 6.3.3). Barcodes and their quiet zones must stay off seams, folds, flaps, perforations, tight curves and rough textures (GS1 General Specifications, 6.2.3.3).
How big must an EAN-13 be?
GS1 sizes the EAN-13 by where the item is scanned. At the target X-dimension of 0.330 mm, the old “100 % magnification”, the symbol is 37.29 mm wide including quiet zones and 22.85 mm high (GS1 General Specifications, 5.12.2.2). Items scanned at the till and also in distribution, for example a case of water that is sold as one unit, need the larger sizes of table 3.
| Parameter | Scanned at the till only (table 1) | Scanned at the till and in distribution (table 3) |
|---|---|---|
| X-dimension | Minimum 0.264 mm, target 0.330 mm, maximum 0.660 mm | Minimum 0.495 mm, target and maximum 0.660 mm |
| Minimum bar height | 18.28 mm at minimum X, 22.85 mm at target X, 45.70 mm at maximum X | 34.28 mm at minimum X, 45.70 mm at target and maximum X |
| Quiet Zone | 11X left, 7X right | 11X left, 7X right |
| Minimum print quality | 1.5/06/660 | 1.5/06/660 |
| Below the minimum | X from 0.249 mm only for on-demand printing such as thermal or laser; never truncate the bar height | Same rule |
GS1 is firm on two points. The height must not be cut below the minimum for the X-dimension used, because a truncated code reads only when the pack crosses the scanner at the right angle, and truncation is allowed only where unavoidable, such as a tightly curved surface (GS1 General Specifications, 6.3.3.4). And the area for the symbol and quiet zones should never be smaller than the area for a 0.264 mm X-dimension (GS1 General Specifications, table 1 note).
What about bottles, cans and other round packs?
On a curved surface the ends of a wide barcode disappear round the curve, so one camera or scanner cannot see both ends. GS1 requires the angle between the tangent at the centre of the code and the tangent at its outer guard bars to stay below 30 degrees; above that, the bars must run round the container, in ladder orientation (GS1 General Specifications, 6.2.3.2). GS1’s Table 6-1 turns that into container diameters:
| Container diameter | Largest X-dimension for picket-fence EAN-13 | What it means |
|---|---|---|
| 30 mm or less, up to 45 mm | None: too small for picket fence | Rotate the barcode to ladder orientation |
| 60 mm | 0.330 mm (the target size) | A nominal-size EAN-13 just fits in picket fence |
| 80 mm | 0.446 mm | Room for a larger code |
| 120 mm or more | 0.660 mm (the maximum) | Any EAN-13 size fits |
Put the other way round, GS1 Table 6-2 gives a minimum container diameter of 48 mm for a picket-fence EAN-13 at the minimum 0.264 mm X-dimension, and 120 mm at the maximum 0.660 mm (GS1 General Specifications, Table 6-2). For a line reader, a ladder code on a round bottle is easier: the bars wrap round the bottle, the code stays readable from one side, and the reader only needs the label facing it, or the bottle rotated past it.
How is it read on a packaging line?
A fixed code reader or a smart camera with code tools reads the EAN-13 as the pack passes. The useful check is not only “a barcode is there” but “the GTIN is the one this line should be packing”: the expected GTIN comes from the PLC, the recipe or the MES, and a mismatch rejects the pack. This is how a label or sleeve from the previous product is caught after a changeover. See label inspection for the wider label check.
| Aspect | EAN-13 | Limit |
|---|---|---|
| Carries | A GTIN-13: the product number only | No batch, date or serial number |
| Where it goes | The consumer unit scanned at the till | Not intended for cases that are never scanned at a till |
| How it is printed | Usually pre-printed with the artwork, sometimes on a label | Changes only when the artwork or the GTIN changes |
| What a line reader checks | Present, readable, the right GTIN for the product running | Not the print grade a retailer’s verifier gives |
A sensible station design for consumer units:
- Where: after labelling or carton forming, before packs are grouped, where each pack passes singly with the code facing a known direction.
- Field of view: wide enough for the full symbol and its quiet zones plus the position tolerance of the pack on the conveyor. For curved packs in picket fence, add a second reader or a rotation.
- Expected GTIN: loaded with the recipe at changeover, never typed in by hand at the reader.
- Outcome: no-read and wrong GTIN both reject; the reject is confirmed by a sensor.
- Records: counts of good, no-read and wrong reads per batch, and images of failures.
What goes wrong with EAN-13 on the line?
The first fault in the table is a content fault a line reader catches outright. The others are print and design faults that a verifier grades; a line reader sees them indirectly, as codes that read poorly or not at all.
| Fault | Usual cause | What the line sees | Who fixes it |
|---|---|---|---|
| Wrong product’s barcode | Labels, sleeves or cartons from the previous run left at changeover | A perfect read of the wrong GTIN | Line clearance plus a GTIN check in the reader |
| Low contrast | Dark bars on a dark, metallic or red-printed background | No-reads or low decode margin | Artwork: dark bars on a light background |
| Truncated height or quiet zone | Artwork squeezed to make room for other graphics | Reads only when the pack is square to the reader | Artwork and print approval |
| Wrapped round a tight curve | Picket-fence code on a small bottle or can | Only part of the code visible to one camera | Ladder orientation, or two readers |
| Bar width gain or loss | Ink spread on absorbent stock, worn plate | Reads with a falling decode margin | Printer: bar-width reduction, plate change |
| Barcode on a seam, flap or fold | Artwork layout | Intermittent no-reads after forming or sealing | Artwork: GS1 obstacles rule |
A related trap is a pack carrying two different barcodes, for example an EAN-13 for the unit and an old code from a promotion. GS1’s rule is that barcodes for different GTINs must never be visible on one item (GS1 General Specifications, 6.2.1). A reader set to accept only the expected GTIN, and to flag two codes in one image, finds this on the line.
Does a line reader replace a barcode verification report?
No. Many South African retailers require a GS1 South Africa barcode test report as a mandatory step in product listing; GS1 South Africa tests to ISO 15416 methods and checks size, colour, print quality and numbering (GS1 South Africa verification service). ISO/IEC 15416 is the print quality test specification for linear symbols (ISO/IEC 15416:2025). A line reader confirms every pack is readable and correct, which is a different job: a verification report covers samples, a line reader covers every pack. More on ISO/IEC 15416 and barcode verification and grading.
Frequently asked questions
Can a camera tell if the EAN-13 belongs to a different product?
Yes, when it is told which product is running. The reader decodes the GTIN and compares it with the expected GTIN from the recipe or PLC; any other GTIN is rejected, even if the barcode itself prints and reads perfectly.
Is an EAN-13 barcode enough for traceability?
No. It identifies the product, not the batch or date. Traceability on the pack comes from the printed lot and date code, or from a 2D code that carries them as GS1 Application Identifiers.
What is the smallest EAN-13 allowed?
For items scanned only at the till, GS1 sets a minimum X-dimension of 0.264 mm with a minimum bar height of 18.28 mm. Thermal or laser printing on demand may go down to 0.249 mm. The height must not be truncated below the minimum.
Should the EAN-13 on a bottle run round it or along it?
It depends on the diameter. GS1 Table 6-1 says a container of 45 mm diameter or less is too small for a picket-fence EAN-13, so the bars must run round it in ladder orientation; from about 60 mm a nominal-size code fits upright.
Sources
- GS1 General Specifications, Release 26.0 (Jan 2026), GS1 South Africa copy: 5.2.2, 5.12.2.2, 5.12.3.1, 5.12.3.3, 6.2, 6.3.3, Tables 6-1 and 6-2, 7.9.1 (standard, checked 2026-10-27)
- GS1 South Africa: barcode verification service (standards body page, checked 2026-10-27)
- GS1 South Africa: barcode types (standards body page, checked 2026-10-27)
- ISO/IEC 15416:2025, bar code print quality test specification for linear symbols (ISO catalogue page)