Windows Server core licensing calculator
Core licences and 2-core packs for Windows Server Standard or Datacenter, with the 8-core and 16-core minimums applied.
The most that can run on one host at once, including after a failover.
Runs in your browser. Nothing you type is sent to the server.
About this tool
Windows Server is licensed by physical core. Every processor needs at least 8 core licences and every server at least 16, and licences are sold in packs of 2 cores. Standard covers two virtual machines for each full set of licences, so more machines on the same host means licensing the host's cores again; Datacenter covers any number. Enter your hosts and the number of virtual machines to see the count. Client access licences, Software Assurance, and clusters where machines can move between hosts are not included: every host a machine can run on must be licensed for it. The rules were checked in 2026; confirm against Microsoft's current licensing terms before you buy.