To calculate your Global Model Number you can either
build your own tool using this formula
or use the
GMN Generator Tool
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.