Global Model Number (GMN)

The GMN is the GS1 key used to identify a grouped family of products or a model.

The Global Model Number enables companies to uniquely identify the product model through the entire life cycle of the product: design - production – procurement – use – maintenance - disposal.
Examples of where the Global Model Number might be used include products that are sold under different versions, with different colours or supporting languages, but otherwise technically are the same. Other examples include medical devices, for which conformity assessment can take considerable time and effort before a product can be released on a market.
In the European Union (EU), the GMN supports the implementation of the requirements of the Basic UDI-DI under the EU Unique Device Identification (UDI) regulations on medical devices and in-vitro diagnostics devices.

Global Model Number Generator


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.

Certain types of products require communication with trading partners and other stakeholders such as regulators before a product goes into production or is available within 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 are otherwise technically 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 products can create enormous efficiency.

Other examples of where use of a GMN may be beneficial, include a sewing pattern (e.g., in apparel sector), a form/material/classification scheme (e.g., in construction sector), or a product line (e.g., in cosmetic sector).
The GMN was initially introduced for the identification of a product model or product family for regulated medical devices in the European Union (EU), however the GS1 standards ensure its applicability across industry sectors.

Important note: GMN is a GS1 identification key that is not intended for use in a data carrier, except for the construction industry. This means that it will not appear in a barcode or an RFID tag on a product and will also not be printed in human readable text on the product. The GMN is not for use in identifying trade items physical forms, it is instead an identifier that will be used within databases.

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 device 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. It 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 UDI-DI (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).

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 the product item master data, for example through GS1’s Global Data Synchronisation Network (GDSN).

All GMN level attributes are common for all GTINs associated with it. Where changes are made to core attributes of family products, it may be necessary to allocate a new Global Model Number. Please refer to GS1 General Specifications for the rules relating to GMN changes.

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).

The GMN comprises the GS1 Company Prefix of the company assigning the identifier, a model reference and a mandatory check character pair.
GS1 Company Prefix: Allocated by GS1 Member Organisation to the brand owner and it may vary from four to twelve digits.  For GS1 Australia the GS1 Company prefix will either be seven or eight digits long.

Model reference: The structure and content of the model reference is at the discretion of the brand owner.

Check character pair: The last two digits are the mandatory check characters. More information on how to calculate these check characters is available on GS1’s GMN generator website.

Important:  Note that the GMN generator tool is case sensitive. The calculation of the Check character pair is quite technical and we recommend you use this tool. If you are interested to know how to calculate it manually, please refer to Check Character calculation (for alphanumeric keys) in Section 7 of General Specifications.

The AI for GMN is AI(8013)

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The decision regarding when to change a GMN in the context of the EU MDR & IVDR regulations (where used as a Basic UDI-DI) is determined by the regulation.

Refer to General Specifications (Section 4 regarding Allocation rules)