Barcode Formats – EAN13 & UPC Code

There are 2 main formats for barcode numbers – 13-digit EAN-13 barcode numbers and 12-digit UPC numbers. The UPC numbers (also called UPC-A or UPC-12) are most commonly used in the USA, and the EAN13 numbers are used in the rest of the world. They are actually part of the same system – the UPC numbers are a subset of the larger EAN-13 barcode number system. These numbers are protected – so you need to purchase the barcode numbers if you want to use them on your retail products.

We tend to supply barcode numbers in 13-digit EAN-13 format, with a leading 0 (e.g. 0799439112766 ). However, these numbers also can be used in 12-digit UPC Barcode format without the leading 0 (e.g. 799439112766 ). The actual bars produced for both of these are identical (see the picture below).

In the UK, it is common to print the barcode on products in the EAN-13 format. However, certain retailers have software systems that don’t like numbers with a leading 0. They will prefer to use your barcode in the 12-digit format (e.g. 799439112766 ). This is fine. The number is still the same and still unique and will work OK. You can let the retailer work out which version of your barcode number they will use.

Follow this link to our Barcode Shop if you need to buy a barcode for your retail product.

And look here for more information about what makes Barcode1 UK different.



Why this occurs?

A digit is encoded into every barcode is 7 blocks of either black or white, making up each digit. A set of full digits 0-9 is called a parity. Retail barcodes have 2 parities minimum, 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 2 different parities – a left side odd parity and a right side even parity (each with 6 digits) – the parities for these can be seen in the attached.

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 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 6 digits each. 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 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 scanned (i.e. the scanner isn’t reading the digits below the barcode), an EAN-13 barcode with a ‘0’ on the front of it can sometimes be confused by scanners as a UPC barcode without the ‘0’ and vice-versa. This is largely to do with what the software system or scanner is expecting to see. Often this occurs because a barcode that is not linked on the system is scanned – The software has no point of reference for which format the barcode is meant to be and, thus, assumes that it is UPC format. When the number is first added onto the system in the 13 digit format and linked to the system in the system (generally how stores add the barcodes based on the information provided on their buyer form), it tends to scan correctly; as an EAN-13 format barcode.

Very few stores have had some issues with this in the past. And when issues occur, they are generally resolved fairly easily. If you are going to the Musgraves in Ireland, they prefer to fill out your barcode in its UPC format on their buyer form (without the leading ‘0’) state that the format is UPC. If this is done, they have no problems using our barcodes.

Please contact us if you have any questions about this.


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