How many cores do I need to license for Windows Server?

License every physical core in the server, with at least 8 core licenses per physical processor and at least 16 core licenses per server. A single processor with 8 cores or fewer still needs 16 core licenses. Count physical cores, not hyperthreaded logical processors.

How many virtual machines does Windows Server Standard allow?

When all physical cores are licensed, Standard allows two virtual machines, also called operating system environments. To run two more, you license all the physical cores again. Datacenter allows an unlimited number of virtual machines on the licensed server.

What does a Windows Server 16 core license pack cover?

A 16-core pack covers a server with up to 16 physical cores, which is also the minimum any server needs. Examples are one processor with 16 cores or fewer, or two processors with 8 cores each. Larger servers need additional core licenses.

Are CALs included with Windows Server core licenses?

No. Core licenses cover the server itself. Each user or device that accesses the server needs a Windows Server Client Access License, and Remote Desktop users also need RDS CALs. Windows Server Essentials is the exception, because it does not require CALs.

When is Datacenter cheaper than Standard?

Datacenter becomes the better value once you need enough virtual machines that stacking Standard licenses costs more than one Datacenter license. Each extra pair of VMs on Standard means licensing all the cores again, so compare the current prices on the product pages.

Windows Server Core Licensing Explained: How Many Cores to Buy

Windows Server Standard and Datacenter are licensed by the number of physical cores in the server. You license every physical core, with a minimum of 8 core licenses per processor and 16 core licenses per server. Standard then gives you rights to two virtual machines, while Datacenter gives you unlimited virtual machines. Client Access Licenses (CALs) for the people or devices that use the server are separate.

The core licensing rules

Every physical core in the server must be licensed, subject to two minimums. These rules apply to Windows Server 2016, 2019, 2022 and 2025 Standard and Datacenter.

License all physical cores. Count the cores on every processor in the server.
Minimum 8 cores per processor. A 4-core or 6-core processor still counts as 8.
Minimum 16 cores per server. A single processor server still needs 16 core licenses.
Sold in packs. Core licenses come in 2-core packs, and are also commonly sold as 16-core packs, so you can add exactly what you need above the minimum.
Physical cores only. Hyperthreading does not double the count. Ignore logical processors.

How to count cores on your server

Count physical cores, not logical processors. On a running Windows server, open PowerShell and run:

Get-CimInstance Win32_Processor | Select-Object Name, NumberOfCores, NumberOfLogicalProcessors

Add up NumberOfCores for every processor. Task Manager shows the same figure under Performance > CPU as "Cores", next to "Logical processors". For a new server, the processor specification sheet lists cores per processor.

Then apply the minimums:

For each processor, take the larger of its core count or 8.
Add the processor totals together.
If the total is below 16, round up to 16.

Standard vs Datacenter: virtualization rights

The two editions run the same software for most roles. The licensing difference is how many virtual machines (operating system environments) you may run.

	Standard	Datacenter
Virtual machines when all cores are licensed	2	Unlimited
More VMs	License all cores again for each 2 more	Already unlimited
Physical instance	May run Hyper-V to host the VMs	May run Hyper-V to host the VMs
Datacenter-only features	No	Storage Spaces Direct, software-defined networking
Best for	Physical servers and light virtualization	Dense virtualization hosts

The physical operating system can be used to host and manage the virtual machines without counting as one of them. If you run other workloads on the physical installation, it uses one of the Standard edition's two rights.

Licensing individual virtual machines rather than the host is an option tied to Software Assurance or subscription licenses, not to perpetual licenses bought on their own. With a perpetual license, plan on licensing the physical host.

Worked examples

These examples show how the minimums work in practice.

Server	Physical cores	Core licenses needed	Standard VM rights
1 processor, 4 cores	4	16 (server minimum)	2
1 processor, 8 cores	8	16 (server minimum)	2
1 processor, 16 cores	16	16	2
2 processors, 6 cores each	12	16 (8 per processor)	2
2 processors, 12 cores each	24	24	2
2 processors, 16 cores each	32	32	2
1 processor, 24 cores	24	24	2

Example 1: a small office server. One processor with 8 cores. You need 16 core licenses because of the server minimum. A single 16-core pack covers it, whether you buy Standard or Datacenter.

Example 2: two processors with 12 cores each. That is 24 physical cores, so you need 24 core licenses. A 16-core pack plus four 2-core packs covers it.

Example 3: four virtual machines on Standard. A 16-core host running four VMs needs the 16 cores licensed twice: 32 Standard core licenses. Six VMs would need 48.

Example 4: a busy virtualization host. Two processors with 16 cores each is 32 cores. Running ten VMs on Standard means licensing those 32 cores five times, 160 core licenses. Datacenter needs only 32 core licenses for unlimited VMs, so it is usually the cheaper path at that density.

How core count affects the price

Price scales with the number of core licenses you need, so a server's core count decides the cost more than anything else. When you compare "Windows Server 2025 Standard price" or "Windows Server 2022 Datacenter 16 core" listings, check that the pack size matches your server after applying the minimums. A 16-core pack is the right size for most single-processor servers. Larger servers need a 32-core or 64-core pack, or a 16-core pack plus 2-core packs.

Current prices are listed on each product page under /windows-server, including Windows Server 2025, 2022, 2019 and 2016.

CALs are licensed separately

Core licenses let you run the server. Each user or device that connects to it also needs a Windows Server CAL of the same version or later.

User CALs cover one person on any number of devices.
Device CALs cover one device used by any number of people.
RDS CALs are needed in addition for Remote Desktop Services sessions. See RDS CAL user vs device.

Windows Server Essentials (2016 and 2019) works differently. It is designed for small businesses with up to 25 users and 50 devices and does not require CALs.

If the server also runs SQL Server, that is licensed separately as well. See SQL Server licensing explained.

Installing and activating

Once you have the right licenses, follow our guide to installing Windows Server, which covers the evaluation ISO, Desktop Experience vs Server Core, and converting an evaluation to a full version with your product key.

Need help?

If you are not sure how many core licenses your hardware needs, open a ticket at /support with your processor model and the number of virtual machines you plan to run, or call +1-888-470-5516. Free tech support is available 7 days a week.