Understanding the Difference Between EAN-13 and UPC-A Barcodes

UPC-A barcodes are effectively a subset of EAN-13 barcodes. For example, if the first digit of an EAN-13 number is ‘0,’ then the bars of both the EAN-13 and the UPC-A (without the leading ‘0’) will appear identical. However, the human-readable numbers below the bars differ between the two formats, and this placement represents their biggest distinction. Fortunately, most scanners easily read both barcode types.

When Should You Use an EAN-13 vs. a UPC-A?

Traditionally, retailers in the USA have used UPC-A format barcodes, whereas stores throughout the rest of the world have used EAN-13 format barcodes. Nowadays, the majority of global retailers accept either format. Nevertheless, some older systems may only accept one or the other. Therefore, if you are selling your product specifically within the USA, UPC-A format barcodes work best. Conversely, if your product has an international market or you sell outside the USA, an EAN-13 barcode is the better choice.

If you encounter a store that has difficulty reading your EAN-13 or UPC-A barcode, they can either ignore the leading ‘0’ or add one, depending on their system’s digit preference. In doing so, the barcode will read exactly the same as the opposite format—since the bars are identical regardless—and will still remain globally unique.

You can purchase both UPC and EAN-13 numbers here. If you require a UPC-A format barcode, please specify this in the additional information section during checkout.

Why this occurs

The encoding of each digit into a barcode uses 7 blocks of either white or black per digit. A full set of digits 0–9 is called a parity. Retail barcodes contain a minimum of two parities—one for the left side and one for the right side. This design allows scanners to read the barcode upside down and still return the correct number in the right order.

Originally, George Laurer created the 12‑digit UPC system in the 1970s. These barcodes work with two different parities: a left‑side odd parity and a right‑side even parity, each with 6 digits. You can see the parities for these in the attached diagram.

Later, developers introduced the 13‑digit EAN‑13 system as a superset of the UPC barcodes. They deliberately designed this system to work alongside UPC‑A barcodes. Hence, EAN‑13 employs both the left odd parity and the right even parity from UPC, but adds an additional parity—a left‑even parity—for use on a selection of the left‑hand digits.

The left and right halves of the EAN‑13 barcode still divide into 6 digits each. Accordingly, the initial digit determines which combination of the first 6 digits will use the newly created left‑even parity. As a result, no EAN‑13 barcode encodes the first digit directly into the bars; instead, that first digit dictates the encoding pattern for the other digits.

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. This means the bars look the same as a UPC barcode would without the leading ‘0,’ since the UPC version also uses only the odd parity.

How do they scan?

Because scanners read only the actual bars (not the human‑readable digits below), an EAN‑13 barcode with a ‘0’ on the front can sometimes confuse a scanner into interpreting it as a UPC barcode without the ‘0,’ and vice versa. This confusion largely depends on what the scanner or software system expects to see. Often, this occurs when someone scans a barcode that is not yet linked in the system—the software has no reference point for the barcode format, so it assumes a UPC format. However, when a store first adds the number to their system in the 13‑digit format and links it to the product (typically based on the buyer form information), the barcode tends to scan appropriately as an EAN‑13.

Very few stores have encountered issues with this in the past. Moreover, when issues do arise, they generally resolve easily. For instance, if you are supplying Musgraves in Ireland, they prefer that you fill out your barcode in its UPC format on their buyer form—without the leading ‘0’—and clearly state the format as UPC. If you follow this step, they have no problems using our barcodes.

Please contact us if you have any questions about this topic.

 

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