The Azure Hybrid Benefit allows customers with Windows Server licences with SA to use those licences in Azure to license a base virtual machine for Windows Server. If you’re interested in knowing the potential savings this benefit can offer, then there’s an Azure Hybrid Benefit Savings Calculator here: http://bit.ly/2CJWpOf.

Note that it still works on Processor-based licences so if you’ve got Core licences then divide the number of licences by 16 when you input the number of existing licences with SA.