Microsoft Licensing Calculator

Windows Server uses a per-core licensing model. Every physical core must be licensed, with a minimum of 16 cores per server and 8 cores per CPU socket. Licenses are sold in 16-core packs. Example: a server with 2 CPUs and 8 cores each (16 total) requires 1 pack. A server with 2 CPUs and 16 cores each (32 total) requires 2 packs.

Standard supports up to 2 virtual machines per license set. Running more VMs requires stacking, which means purchasing another full set of core licenses for every additional 2 VMs. Datacenter provides unlimited virtualization rights. The crossover point is typically 10 to 12 VMs per host, where stacked Standard exceeds the cost of a single Datacenter license. This calculator shows both prices so you can compare.

If your users access servers from multiple devices (laptop, desktop, phone), User CALs are more economical. One User CAL covers all devices that person uses. If you have shared workstations or kiosks used by multiple people, Device CALs are more economical. One Device CAL covers every user on that machine. This calculator recommends the lowest-cost option based on your counts.

Yes. Remote Desktop Services CALs are required in addition to standard Windows Server CALs for anyone connecting via Remote Desktop, RemoteApp, or a terminal server session. They are a separate line item and cannot be substituted with regular CALs.

That is the most common problem this calculator solves. The four most frequent mistakes: (1) under-licensing cores due to the 16-core minimum, (2) choosing Standard when Datacenter is cheaper at high VM density, (3) forgetting that CALs are a separate purchase from the server license, and (4) not realizing RDS CALs are additive. Run your configuration above to eliminate guesswork.

No. CALs must match or exceed the version of the server being accessed. Windows Server 2022 CALs are not valid for Windows Server 2025. New CALs are required when upgrading your server version.