How to get GS1 compliant labels – in 89 simple steps

Over the past couple of weeks I covered the technical standards and aspects of GS1-Labels and the applicable standards for the food industry, as well as the physical challenges of printing and applying labels within the food industry. Well, it seems that I forgot to cover the administrative challenges on getting GS1 compliant. Here we go….

Step 1: Getting a company prefix from GS1

The first step is that you license a GS1 company prefix. These numbers are issued by the national offices of GS1 in the country the brand owner of a particular range of products is located. Historically, this prefix was 7-digits long in Europe and 6-digits long in the US, both have been harmonized and the length became variable. You still find that most companies have this 7-digit long prefix, but newer registrants may have longer company prefixes, thus shorter room for their item numbers. GS1 started basically running out of room, with 1 Million participants in the system, it was only able to accommodate less than 10 Mio brand owners total. This change was necessary to increase the availability of GS1 beyond that number while staying compatible with the existing system. The only thing important for companies today is, that they length of the prefix is short enough, so that companies can issue enough GTINS for all the brands they produce. With a 7-digit prefix, this would be a 5-digit number (99999), which should be enough. Even an 8-digit prefix would suffice for most organizations, leaving 9999 GTIN’s available. So regardless of anything, step number one is getting that prefix.

Step 2: Building GTIN’s

GTIN’s, or “Global Trade Identification Numbers” are basically worldwide unique item numbers. There is a range of documents written about these numbers in the standardization documents (links above). But in a nutshell, it boils down to this for most companies:

  • The first digit “P” is the packaging indicator. This indicator has been introduced in 2005. Since a lot of companies still have very old systems, some participants don’t have that completely integrated, so that anything different than a “zero” may cause problems with some customers of yours. You want therefore to use that “0″ whenever possible. To stay within the standard, you must use a “9″ for all catch weight items.
  • Next comes the company prefix “CCCCCCC”, which is in most cases 7-digits long. Check for the proper length when building the GTIN! This is the number that has been issued by GS1.
  • Next comes the item number “NNNNN”. In the perfect world, you want to keep this segment of the GTIN identical to the internal item numbers. It is therefore recommended, that you use 5-digit numeric item codes for all your products that you want to label GS1 compliant.
  • The last digit is a checksum “D”. This checksum is calculated and is needed for technical reasons, making sure that the bar code is properly printed and read by scanners. GS1 provides on its website a check digit calculator that allows you to see how this works and check whether you have it right. You can actually calculate the check digit in MS-Excel using these formulas (A1 contains the number w/o check digit):
    • For the check digit alone: =10 – MOD( SUMPRODUCT(MID(A1, {1,2,3,4,5,6,7,8,9,10,11,12,13}, 1) * {3,1,3,1,3,1,3,1,3,1,3,1,3}), 10)
    • For the whole number: =A1 & MOD(10 – MOD( SUMPRODUCT(MID(A1, {1,2,3,4,5,6,7,8,9,10,11,12,13}, 1) * {3,1,3,1,3,1,3,1,3,1,3,1,3}), 10), 10)

So all in all it would be 14 digits: PCCCCCCCNNNNND



Step 3: Choose your bar code!

I don’t believe that there is a real choice to make here, but still. GS1 allows different types of bar codes, but in all reality companies within the food industry must implement a GS1-128 label on all shipping containers. Again, there are different labels on different packaging units such as consumer items, boxes and pallets, and you need to make a choice on each of them. These choices are also dependent on your internal logistics, WMS Systems and other things and are in detailed spelled out in those standards. With GS1-128 as a barcode standard, you have essentially a barcode with variable/configurable content, and you usually wind up with:

  • On pallets: (00) – the so called SSCC number. You may add other data elements to the pallet-id, but in all reality this may cause more problems that solutions. Especially if you deal with mixed pallets. Even pallets with the same GTIN may have eventually different lot numbers on the same pallet. Any additional element you would label on the pallet must be true for all containers on the pallet. This means that any additional element encoded in the barcode puts restrictions on your WMS and order fulfillment process, so the easiest to avoid all that – don’t put anything else on the label unless you absolutely have to.
  • On consumer items: leave it up to the retailer if you can!
  • On the box:
    • (01) GTIN, mandatory
    • (11, 13, 15, 17) one of those dates, based on your preference and customer requirements
    • (310x or 320x) net weight (either in lbs or kgs)
    • (21) or (10) either the serial number (better and more common) or a lot number. Either one ensures traceability.

Use also them also in the sequence as I provided them, it makes the barcode a tiny bit shorter. There are more options, but again, I try to simplify the options for participants in the food supply chain.

Step 4-89: GDSN, EPCIS and other acronyms you don’t understand (yet)!

It never ends. Once you start embracing GS1, implementation of that organization’s standards will never stop. Retailers will ask you to use these numbers in EDI messages for orders and invoices. They want you to electronically share your master data using GDSN (Global Data Synchronization Network) or a national implementation thereof (e.g. ECCNet in Canada), they entice you to participate in the rapid recall exchange for electronic recall and notification management. It really never ends. The first three steps get you basically on the road, but once you have completed step 3, you reach crossroads and you need to decide what road to take next coming again and again to the same crossroads with just different possible avenues to take.


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