UPC-A Barcodes are basically a subset of EAN-13 Barcodes. If the first digit of the EAN-13 number is a ‘0’, then the bars will be of both the EAN-13 and the UPC-A (without the leading ‘0’) will be identical. The displacement of the human readable numbers below differ between the UPC-A and EAN-13 barcodes. However, this is the biggest difference. Both barcodes can be scanned by the majority of scanners easily.
When Should You Use an EAN-13 vs. a UPC-A?
UPC-A Format barcodes have in tradition been used in the USA, whereas EAN-13 format barcodes have been used throughout the rest of the world. Nowadays, the majority of stores throughout the world accept barcodes in either format. However, there might be some older systems that only accept one or the other. This means that if your product is being sold in the USA, the UPC-A format barcodes are best, however, if your product is international, or sold in a country other than the USA, an EAN-13 Barcode is best.
If you come across a store that struggles to read your EAN-13 or UPC-A Barcode, they can either ignore the leading ‘0’ or add a leading ‘0’ depending on which format their system prefers. If this is done, the barcode will read the same as the opposite format (as the bars are identical regardless), and will still be globally unique.
Why this happens
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 side 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 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. Often 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.
Please contact us if you have any questions about this.