Model Identification – Global Model Number (GMN)

What are GMNs?

The Global Model Number is a GS1 key used to identify a grouped family of products or a model.


The GMN enables companies to uniquely identify and manage like products throughout the entire product life cycle: design, conformance assessments, production, procurement, use, maintenance, performance monitoring, recalls and disposal.

How are GMNs used?

Certain types of products require communication with trading partners and other stakeholders such as regulators before a product goes into production or is available in a market. The ability to group products under the same model or family, using a GMN, streamlines the process to manage product specifications and other market-based information in a consistent way.

Examples of products where they may be managed as models or families include products with various versions, capacities, colours, sizes or supported languages, but that are otherwise technically are the same design. One technical example is medical devices, where conformity assessments are completed before a product is released to a market, these can take considerable time and effort but completing this process for a family of product can create enormous efficiency.

The GMN will initially be used for the identification of product model or product family for regulated medical devices in the EU. Other applications may be added in the future, after approval through the GS1 Standards Management Process (GSMP).  Further information of how the GMN is used within healthcare is detailed specifically below.


GMNs and Master Data

In order to enable effective grouping of a family of products, the GMN can be included as an attribute of each trade item within the family or model. Where needed the GMN can be communicated to trading partners as part of product item master data via methods including data synchronisation (GDSN).

GMN in Healthcare

How is GMN used for Regulated Healthcare items?

In the European Union (EU), the GMN supports implementation of the requirements of Basic UDI-DI under the EU Unique Device Identification (UDI) regulations on medical devices and in vitro diagnostic medical devices.

The Basic UDI-DI is the main key for medical devices records in the UDI regulatory database EUDAMED and is referenced in relevant certificates and in EU declarations of conformity.

For regulated healthcare medical devices, the GMN is the GS1 identification key that supports the implementation of the Basic UDI-DI requirements.

  • Basic UDI-DI (GMN) is used for medical device registration and is assigned independent of packaging/labelling and is different from the identifier for trade items in the supply chain (UDI-DI(GTIN)).
  • All Basic UDI-DI (GMN) level attributes (in the UDI regulatory database) are common for all GTINs associated with it.
  • All attributes across all UDI-DIs (GTINs) associated with one Basic UDI-DI (GMN) may not be common.
  • The Basic UDI-DI (GMN) is used for device registration in the registration database. The UDI-DI (GTIN) is used for trade item identification in the UDI database. UDI-DI (GTIN) and Basic UDIDI (GMN) allocation may occur before, in parallel, or after each other and attribution and/or linkage between the entities is only possible once both entities exist. For this reason, allocation of UDI-DI (GTIN) and Basic UDI-DI (GMN) shall be made independent of one another.
  • Brand owners are responsible for the assignment of Basic UDI-DI (GMN) and UDI-DI (GTIN.)

Important notes:

  • In accordance with the EU regulations the Basic UDI-DI (GMN) SHALL NOT be encoded in a data carrier.
  • The regulated medical device UDI-DI (GTIN) SHALL NOT be used as a replacement for Basic UDI-DI (GMN).

GMNs and Master Data in healthcare

For regulated healthcare medical devices, the Basic UDI-DI is the key element in the UDI regulatory database for medical devices. An identifier for a device product family, the GMN will link medical device trade item(s) identified by GTIN(s) in the UDI database to pre-market and post-market activities (e.g., certificates, declaration of conformity, vigilance, market surveillance and clinical investigations). This highlights the relationship between Basic UDI-DI (GMN) and UDI-DI (GTIN.)


Creating GMNs

The GMN comprises the GS1 Company Prefix of the company assigning the identifier, a model reference and check characters. The model reference is alphanumeric. A GMN is a variable length identifier, with a maximum length of 25 characters in EU regulated healthcare including a 2-digit check sum or 30 characters in other applications once they are ratified.

GS1 Company Prefix: This will be assigned to you by GS1 Australia and will vary in length from seven to nine digits. 

Model reference: This is assigned by you and we recommend that you begin with zeroes and increase the count sequentially.

Mandatory check characters (Healthcare): Please note that the Basic UDI-DI (GMN) has a maximum length of 25 characters, including two mandatory check characters. These can be calculated thanks to the GS1 check character calculator dedicated webpage.