What is a GS1 barcode?
A GS1 barcode is a machine-readable symbol used to encode a GS1 identifier, such as a Global Trade Item Number (GTIN). Depending on the barcode type, it can also carry attributes such as batch, lot, serial or date information.
A scanner or image-based reader can capture the encoded data electronically, and the symbol may be one-dimensional or two-dimensional.
At a glance:
- Identifiers cover products, shipments and locations; attributes include serial, batch, lot or date data in plain, GS1 element string or GS1 Digital Link URI.
- Linear barcodes encode data with variable-width bars and spaces. Two-dimensional barcodes encode across width and height and can hold more data in less space.
- GS1-128 is a Code 128 subset that uses FNC1 and Application Identifiers to carry data such as GTIN, batch, serial and expiry information.
- On a production line, a scanner captures encoded data. Barcode verification grades symbol quality, while traceability depends on the wider data and process system.
The right GS1 barcode depends on what needs to be identified, what additional data must travel with it, and where the code will be read. Choosing the barcode format is separate from verifying print quality or designing the wider traceability process.
What can a GS1 barcode encode?
A GS1 barcode can carry an identification key alone or, in supported symbologies, additional attributes. The syntax determines how that information is represented in the encoded data.
Identifiers for products, shipments and locations
GS1 identification keys can refer to products, shipments and locations. The identifier tells the system what entity the barcode is identifying, while attributes add information about that entity.
Attributes and GS1 syntax options
For GS1 barcodes, the three encoded-data syntaxes are plain, GS1 element string and GS1 Digital Link URI. Plain syntax carries an identification key without additional syntactic features, while the other two can represent GS1 identifiers and attributes using Application Identifiers.
In production environments, identification systems can combine barcode scanning with vision and other Auto-ID functions to capture and check encoded data on the line.
What GS1 barcode formats are described?
GS1 uses one-dimensional and two-dimensional barcode symbols. GS1-128 is one 1D symbology that carries GS1 data structured with Application Identifiers.
Linear barcode construction
Linear GS1 barcodes use variable-width bars and spaces. Their data is arranged along a single dimension, unlike 2D symbols, which encode data across both width and height.
Two-dimensional barcode patterns and capacity
Two-dimensional GS1 barcodes encode data across both width and height. They can hold more data than 1D barcodes while remaining physically smaller.
Where codes are read automatically on a production line, a fixed mount barcode scanner can provide hands-free capture without manual presentation.
GS1-128 structure and data examples
GS1-128 is a subset of Code 128. It places a Function 1 character (FNC1) after the start character so scanners and software can recognise the symbol as carrying GS1 data. Each data field is preceded by an Application Identifier that defines the meaning and format of the following value. Examples include GTIN, batch or lot, serial and expiry data.
Where GS1 barcodes are produced on labels, the selected industrial label printer also needs to suit the required media, production environment and printing application.
What is the difference between a GTIN and a GS1 barcode?
A GTIN is an identification number for a trade item. A GS1 barcode is the machine-readable data carrier that can encode a GTIN, and some GS1 barcode types can carry additional attribute data as well.
GTIN as the identification number
The GTIN identifies the trade item itself. It can be encoded in several GS1 barcode types and may also be printed in human-readable form alongside the symbol.
GS1 barcode as the machine-readable symbol
The barcode is the machine-readable data carrier. This means a GTIN and a GS1 barcode are not interchangeable terms: one is identification data, while the other is the symbol that carries it.
Additional attribute data
In GS1 symbologies that use Application Identifiers, the AI tells software how to interpret the following field, for example as a batch or lot number, serial number or expiry date.
Reading the encoded data is also separate from vision inspection, which can assess broader visible criteria such as label presence, barcode readability and packaging features.
How are GS1 barcodes structured and used?
GS1 barcodes use defined identification keys, data attributes and barcode structures for use in business applications.
GS1 barcode requirements
The GS1 system covers identification keys, data attributes, barcode symbologies and related application requirements.
Barcode and identification-key use
For a GS1 barcode project, the identification data needs to be structured, encoded and used according to the applicable GS1 requirements.
For the move towards richer 2D retail codes, ALS Identify’s guide to GS1 Sunrise 2027 explains the implications for printing, verification, traceability and production-line preparation.
ALS Identify barcode readers for GS1 barcode reading
For a GS1 barcode application, the reader must support the selected symbology and the way the code is presented on the line. ALS Identify’s barcode reader range includes fixed-mount and handheld options.
Review the range when assessing the reader requirement for your production line. Get in touch with the ALS Identify team to discuss your GS1 barcode reading requirements.
