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Barcode Format

While we can supply barcodes in either EAN-13 format of UPC-A format, we mainly supply them in EAN-13 format. EAN-13 format is the most common format worldwide. Canada and the USA are the only countries who use UPC-A barcodes. However even if you have printed our EAN-13 barcodes on your product, and now require a UPC-A barcode for a particular store (while the rest still prefer the EAN-13 format), the retailer can simply be instructed to ignore the leading ‘0’ on the front of the EAN-13. This means it can be treated in exactly the same way as a UPC-A 12 digit barcode. The actual barcodes for the EAN-13 and the UPC-A without the leading ‘0’ are identical. Barcode scanners therefore scan them in exactly the same way.

Please see below the example image



Why this occurs?

The way a digit is encoded into every barcode is 7 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 1970’s by George Laurer. The UPC barcodes work with 2 different parities. There is a left side odd parity and a right side even parity (each with 6 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 side of the EAN-13 barcodes are still divided into 6 digits each. So the initial digit determines which combination of the first 6 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 6 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. This can occur when a barcode is not entered on the retailer’s database. The software has no point of reference for what format the barcode should be. Hence the software 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. If you are going in the Musgraves in Ireland, Musgraves prefer that you fill out your barcode in it’s UPC format on their buyer form (without the leading ‘0’) and state that the format is UPC.

Please contact us if you have any questions about this.