For Windows Server 2016 Essentials edition, CALs are not required. When a customer purchases a Windows Server OS license (Windows Server 2016 Datacenter edition for example), they receive a license that allows them to install the operating system onto the server.

Do I need Windows Server CALs?

CALs are required by Microsoft licensing for all users or devices that access Windows Server Standard or Windows Server Datacenter. When a customer buys Windows Server Standard or Datacenter, they receive a server license that allows them to install the operating system on one computer.

How many calories do I need Windows Server?

You need 1 CAL per user. 1 CAL is good for unlimited servers assuming there running the same OS, and older.