The Global Language of Business

Generate or validate the GMN

Note: the GMN (Basic UDI-DI) is used for regulated healthcare medical devices under the EU MDR and EU IVDR. The GMN generator is used to generate the GMN based on a GS1 Company Prefix and an internal number, or model reference.

*(for GMN validation only)

Caution: All characters in the GMN are case sensitive

Button definitions

Calculate > Calculate your check character pair from your GMN (Basic UDI-DI) without check characters.

Validate > Perform checks on the complete GMN (Basic UDI-DI) including check characters.

Structure of the Basic UDI-DI (GMN)

The last two characters of the basic UDI-DI are check characters calculated on the previous characters used. The calculator is specifically for a maximum of 25 characters including the check character pair for the Basic UDI-DI. Use our check character calculator above to calculate the check character pair.

Structure of the basic UDI-DI (GMN)


What is a check character?

The check character pair are two uppercase alpha and numeric characters used to detect potential character keying and encoding errors. The GMN (Basic UDI-DI) has a mandatory check character pair.

How does the GMN generator work?

The check character calculator uses an algorithm, based on other numbers and characters in the GMN. See how the check characters are calculated. You can also refer to our GMN helper libraries for support.


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    Phone: + 1 937 435 3870

    300 Princeton South Corporate Center

    Ewing Township, New Jersey 08628

    United States

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