Chris Van Wesep, shows how you can use your on-premises Windows Server licenses with Software Assurance to deploy Azure virtual machines for your workloads, using the Azure Hybrid Use Benefit.
For every 100 Window server licenses, you can run up to 200 virtual Machines with a potential savings of over $300,000 a year based on the popular D3-V2 VM size.
More information on this can be found here: aka.ms/HybridUseBenefits
