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Barcode Formats – EAN13 & UPC Code

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

We normally supply barcode numbers in 13-digit EAN-13 format, with a leading 0 (e.g. 0799439112766 ). However, these numbers can also 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, some retailers have software systems that don’t like numbers with a leading 0, and hence 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.

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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). 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 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 an EAN-13 barcode starting with a ‘0’ 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 yet inked 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.

Please contact us if you have any questions about this.


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