Coded everything for a good placement

What is a barcode? Coding and symbols

The GS1 coding standard is based on the principle of unambiguity, which determines that each product variant must have a unique code that identifies it, provided that the variant is clear and relevant for the partner in the supply chain, but mainly for the end user.

The code that identifies the different product formats and packaging units is known under the name GTIN code (Global Trade Item Number) or global article number.

The GTIN code (Global Trade Identification Number) or the global article number is a unique, universal and unambiguous numbering that is used to identify every sales unit whose predefined information you want to access and which is assessed, ordered or invoiced at every point in the supply chain can be.

The GS1 coding standards can also be used to locate the locations of warehouses, invoices, delivery notes, orders, people, etc.


NOTE: Two different sales units cannot be identified with the same GTIN code and one and the same unit cannot be identified with more than one GTIN code.

DANGER: The owner of the trademark is responsible for assigning the GTIN code to a product.


Guide to the introduction of coding



Symbolizing means displaying the GTIN code assigned to the product graphically using lines and spaces or using two-dimensional codes. The efficiency of reading depends on the correct characters of the symbol. The existing GS1 standard symbols are listed below:


Learn more about these symbols


Guide to the introduction of coding


Creation of a catalog


a) Creation of an internal identification number. The length of this number is irrelevant, including whether it is alphanumeric or not. The more informative the number is for your company, the better. When creating a catalog, it is important to consider all of the packaging hierarchies in which these products can be commercialized. (Figure: Example of a catalog with 3 columns: internal identification number, description and GTIN)


b) Add a second column with the product description. This makes it easier for your partners to identify your products.


c) In the third column, all products listed in the company catalog are coded by assigning a GTIN code.



Assignment of a GTIN code


The GTIN code is obtained by completing the company code assigned by the AECOC (Spanish Association for Commercial Coding) with a consecutive number and then calculating the check digit.


The internal identification number must not be used to complete the company GTIN code, as assigning a meaning reduces the coding options.


Sales units

The products that are intended for retail, i.e. the sales units, must always be coded with a GTIN-13 code.


Packing units

Packaging units can be identified by a GTIN-13 code that differs from the GTIN-13 code of the sales unit contained or by a GTIN-14 code. Both options are valid under the GS1 coding standard.



Calculation of the check digit


The GTIN-13 code is completed by adding the check digit (the AECOC provides an application on its website that can be used to calculate the check digit). In addition to the registration documents, you will also receive an APP to carry out this calculation. The calculation on your own is also very easy, you just have to follow the following three steps:


a) The code is numbered from right to left, the digits in an even place are multiplied by 1 and the digits in an odd place by 3.


b) The values ​​of the results obtained are to be added up.


c) Now determine the tens digit above this sum and subtract the previously calculated sum from it. The result obtained is then the check digit.





The GTIN code must always be changed if the following applies:

  • Change in product properties (size, color, aroma, etc.)
  • Change of dimensions.
  • Change in weight.
  • With multipacks.
  • For products whose container or packaging has changed physically.
  • In the case of products whose recipe or composition has changed so that the end consumer will perceive them.
  • Additions that change the dimensions.
  • Variants that serve to promote sales



A packaging unit is a collection of sales units, the purpose of which is to simplify their handling with regard to shipping, handover, receipt, etc.


All packaging units can be separated according to their respective sales units.


A packaging unit can be identified by assigning a GTIN-13 code that differs from the sales unit it contains.


It is also possible to identify the packaging unit with a GTIN-14 code. This is obtained by placing a type of packaging, also known as a logistics variant, in front of the GTIN-13 code of the sales unit.


The type of packaging is the number on the left-hand side of the GTIN-14 code of the sales unit.


This digit can have a value from 1 to 8.



IMPORTANT: The 0 must not be used here, otherwise the code of the packaging unit could be confused with that of the sales unit. And the 9 must not be used as it is reserved for coding products with variable weight.


Finally, one must also take into account that the value of the check digit of the new code will change.


NOTE: The GTIN-14 code was previously known as EAN-14 or DUN-14. The ITF 14 barcode is the graphic, symbol, or drawing of the GTIN-14.



With the help of the GS1-128 code, the aforementioned codes (GTIN-13 and GTIN-14) can be completed with product-relevant information or features in a modular and standardized manner using so-called data identifiers.



Data identifiers are prefixed numbers that are used to assign a clear meaning to the following standard data. Each data identifier identifies the meaning and the format of the internationally standardized data that follow it.


A feature of these data identifiers is that they can be chained, i.e. the possibility of concatenating various pieces of information in a single code and thus forming a data chain with all the necessary information.


A primary application of the GS1-128 code in the consumer goods industry is its use for tracing or checking products through the unique identification of each container or shipping unit with a number, the IA (00), also known as the Serial Shipping Container Code (SSCC) or shipping unit number (NVE).



The SSCC or pallet number acts as a serial number of the shipping unit to be labeled.


It is valid for one year from the date of dispatch. The combination of SSCC and the EDI message (DESADV message) provides the company with all the information necessary for the traceability of its products.



Symbolization is the graphic representation by means of lines and spaces in the code assigned to the product.


The correct reading of the code on the first attempt depends on the characteristics used to create the symbol.


Only the most important and common features are considered below




Most important points to consider when creating a GTIN-13 code:

  • Dimensions.
  • Edge zones
  • Colours.
  • placement
  • Print quality.



1. Dimensions


The size of a GTIN code is determined by three factors: the type of printing technology, the material to be printed on, and the environment in which the code is read.

Choosing the symbol size based on the package design is a mistake that can result in the code not being read in the end.



The dimensions given in the table apply to sales units and relate to the space between the edge characters.


2. Edge zones


The dimensions mentioned above include the space available for the edge zones before and after the start and stop characters of the GTIN code.

These edge zones must be strictly adhered to.

Occupying these areas with text, images, etc. or printing the code too close to the edge of the packaging leads to incorrect reading of the same.


3. Colors


Any color combination can be used as long as the colors are displayed with sufficient contrast for the scanner. General requirements:

  • Always use dark lines on light surfaces.
  • Never red lines.
  • Metallic colors are not recommended.



4th placement


Correct reading and ergonomics for the staff working at the point of sale depend on the correct placement of the GTIN code.


It is recommended to place the code on the underside of the product, which is determined by the shape and graphic design of the packaging.


If the underside cannot be printed / labeled, the code should be placed on the back of the packaging and near the underside.


The code must be printed on areas that are free of coatings, overlaps, folds or bends less than 5 mm.


If the product is packaged in bulk, it must be ensured that the complete code appears on the packaging. Placing the code near the edge of the product or on an uneven surface, covering it with a heat seal fold, etc. increases the risk that this code cannot be read correctly.


5. Print quality


The deviations in the line width result from inaccurate printing processes or the use of printing templates that do not meet the specifications or have not been specially prepared for the type of printing technology and the surface to be printed.

This then causes lines that are too thick or too thin that the scanner cannot read properly.


Main points to consider when creating a GTIN-14 code:

  • Dimensions.
  • Placement. (The other points - edge zones, colors and print quality - match the points mentioned for the GTIN-13 code)


1. Dimensions


As with the GTIN-13 code, the size of the GTIN-14 code depends on the print quality and the environment in which the code is read.



2nd placement


It is recommended to place the code on two adjacent sides of the shipping unit.


The bottom of the code must be at least 32 mm from the bottom of the shipping unit.


The minimum distance between the code and the vertical edges of the packaging unit must be 19 mm and include the edge zones.



Usually the GS1-128 label is used for pallets due to traceability and the additional information.



An indispensable requirement for the GS1-128 label is that all information shown in the barcode must be human-readable in order to enable manual input of the data in the event of a malfunction in the scanning system, so that the operator does not necessarily have to know the meaning of each individual data identifier.



Placement of the code on pallets:

  • Pallets with a height of less than 40 cm. As high as possible without affecting the width of the code and more than 50 mm from the vertical edge, including the edges.
  • Pallets over 40 cm. At a height between 400 and 800 mm from the pallet floor and more than 50 mm from the vertical edge, including the edge zones.