To how many Microsoft Windows SQL Server licenses should I subscribe per virtual machine?

The total number of Microsoft Windows SQL Server licenses you subscribe to is proportional to the number of vCores in your virtual machine (VM). The number of licenses is non-divisible.

One license can be used for up to 4vCores. For every 4 additional vCores, you must subscribe to one additional license. An exception applies for Microsoft Windows SQL Server licenses, since you must subscribe to a minimum of 2 licenses, regardless of the number of vCores.

This means that if your VM contains 4 vCores, you must subscribe to 2 Microsoft Windows SQL Server licenses. If your VM contains 5 vCores, you still need 2 licenses. If your VM contains 9 vCores, you reach the next tier, and you must subscribe to 3 licenses, and so on.

When you subscribe to the Microsoft Windows SQL Server software, you automatically subscribe to Microsoft Server licenses.