Barcode Formats

We supply barcodes mainly in EAN-13 format. While we can supply in either EAN-13 or UPC-A formats, EAN-13 is more common worldwide. The majority of retailers prefer EAN-13. In some cases, a retailer may insist on a UPC-A 12-digit barcode. Our EAN-13 barcodes are easy to turn into 12-digit barcodes by simply removing the leading ‘0’. In this case, the barcodes will scan in exactly the same way, but the barcode will only have 12 digits, which will work for the retailers’ system.

Please see below for an example of barcode formats. The bars are identical.

07 EAN-UPC Barcode Formats

Why this occurs?

The way a digit is encoded into every barcode is seven blocks of either white or black making up each digit.  A full set of digits 0-9 is called a parity. Retail barcodes have a minimum of 2 parities, one for the left side and one for the right. This is so they can be scanned upside down and still return the correct number the right way around.

Originally the 12-digit UPC system was created in the 1970s by George Laurer. These work with two different parities; a left-side odd parity and a right-side even parity (each with six digits).

Later, a 13-digit EAN-13 system was introduced as a superset of the UPC barcodes. These were deliberately designed to be used in conjunction with UPC-A barcodes. And hence, employed both the left-odd parity and the right-even parity of the UPC barcodes but added an additional parity (a left-even parity) which was to be used on a selection of the left-hand side digits.

The left and right-hand sides of the EAN-13 barcodes are still divided into six digits each. So the initial digit determines which combination of the first six digits will use the newly created left even parity. Hence, in no EAN-13 barcode is the first digit encoded in the barcode. However, it does determine the way the other digits are encoded.

In the case of a leading ‘0’ as with our barcodes, the 0 determines that all of the initial six digits will use the left odd parity, meaning that the bars look the same as a UPC barcode would without the leading ‘0’ as the UPC version also only uses the odd parity.

How do they scan?

Because the actual bars are the only part of the barcode that is scanned (i.e. the scanner isn’t reading the digits below the barcode), an EAN-13 barcode with a ‘0’ on the front can sometimes be confused by scanners as a UPC barcode without the ‘0’ and vice-versa. This is largely to do with what the scanner or software system is expecting to see. Often times this occurs when a barcode that is not linked to the system is scanned. The software has no point of reference for what format the barcode should be, and hence, assumes that it is UPC format. When the number is first added to the system in the 13-digit format and linked to the product in the system (this is generally how stores add the barcodes based on the information provided on their buyer form), it tends to scan appropriately as an EAN-13 format barcode.

Very few stores have had issues with this in the past. And when issues occur, they are generally resolved easily. Musgraves in Ireland prefer that you use UPC format (without the leading ‘0’).

Please contact us if you have any questions about barcode formats.


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