Windows Server License Keys

Genuine Windows Server licences for 2025, 2022, 2019 and 2016, in Standard and Datacenter editions, plus RDS CAL packs for remote desktop access. Keys are emailed instantly after payment, and our team can help you work out exactly what your server needs before you buy.

Windows Server Standard vs Datacenter: which edition do you need?

Both editions run the same Windows Server operating system. The difference is how many virtual machines you are allowed to run and a handful of advanced storage and networking features. If you run one physical server with up to two virtual machines, Standard is usually enough. If you run many virtual machines on the same host or build hyper-converged clusters, choose Datacenter.

Shop by edition: Windows Server 2025 Standard · Windows Server 2025 Datacenter · Windows Server 2022 Standard · Windows Server 2022 Datacenter

Which Windows Server version should you buy?

For a new deployment, pick the newest version your applications support: it gets security updates for the longest. Older versions make sense when a line-of-business application is certified only for a specific release.

Windows Server 2012 R2 no longer receives security updates from Microsoft. Only buy it if you must match an existing legacy environment that cannot be upgraded.

How Windows Server licensing works: cores and CALs

Windows Server is licensed in two layers. You need both.

1. Server licence (per core)

Microsoft licenses Standard and Datacenter by physical core. Every physical core in the server must be licensed, with a minimum of 8 cores per processor and 16 cores per server. A server with two 10-core processors, for example, needs 20 core licences. Check each product page for the number of cores a key covers, and contact us if your server has more cores than that.

2. Client Access Licences (CALs)

Every user or device that connects to the server needs a Windows Server CAL, assigned either per user or per device. Per-user CALs suit staff who connect from several devices; per-device CALs suit shared machines used by shift workers.

3. RDS CALs for remote desktop

If people connect to the server through Remote Desktop Services, each user or device also needs an RDS CAL on top of the standard CAL. Our Windows Server 2025 RDS 50 Device CAL pack, 2022 RDS pack and 2019 RDS pack cover 50 devices each. CAL packs do not include the server operating system. Browse all Server CALs and RDS licences.

Running a database on your server? See our SQL Server licences.

How delivery and activation work

• Your licence key is emailed to you immediately after payment, together with download and installation instructions.
• You install Windows Server from the official Microsoft media and enter the key during setup or afterwards in Settings.
• If activation fails, our support team will help you resolve it or replace the key.

Windows Server licence FAQ

Do I need CALs if I buy a Windows Server licence?

Yes, in most cases. The server licence covers the server itself; each user or device that accesses it needs a Windows Server CAL. Remote desktop access also requires RDS CALs. Some workloads, such as public web servers, do not need CALs.

How many core licences does my server need?

License every physical core, with at least 8 cores per processor and 16 per server. A single 8-core processor still needs 16 core licences; a dual 12-core server needs 24.

Can I run virtual machines with Windows Server Standard?

Yes. A fully licensed Standard server covers two virtual machines. For more, you either license the cores again for every two additional VMs or choose Datacenter, which allows unlimited VMs.

Which CAL version do I need?

CAL compatibility depends on the server version being accessed, and Microsoft's rules differ between releases. The safest choice is CALs matching the version of the server people connect to. If you run mixed versions, tell us your setup and we will match the right CALs.

Are your RDS CAL packs per user or per device?

The RDS packs listed here are Device CALs, each covering 50 devices. Device CALs suit shared computers; if your staff connect from several devices each, ask us about User CALs.