# Windows Server 2025 editions and licensing: Standard, Datacenter and CALs

> What Standard and Datacenter actually license, how OSE counts and CALs work, and why the evaluation edition is the right lab start.

**Tested on**

- Build: 26100.33650
- Edition: Standard / Datacenter
- Architecture: x64
- Evidence: E1
- Verified: 2026-10-27

## The short answer

- **Standard** is for a host with light virtualization: it includes **two OSEs** only when the host does nothing but virtualize; if the host also runs roles such as DNS, you may run **one** OSE under that licence.
- **Datacenter** is for dense virtualization: unlimited OSEs on the licensed host, plus Storage Spaces Direct and Storage Replica.
- **Both** are licensed by **core**, not by processor, and **CALs are separate** for users/devices that access the server (with the usual exceptions).
- **For a lab:** use the **180-day Evaluation**. It is the legal, rebuildable path; do not use “rearm” scripts or KMS tools.

> **Caution: This is an explanation, not a licence sale**
>
> Licensing depends on your agreement, edition, core count and CAL model. Confirm with Microsoft or a licensing partner before production. This page exists so you can ask the right question.

## Standard vs Datacenter

| Dimension | Standard | Datacenter |
|---|---|---|
| Virtual OSEs on the licensed host | 2 (host only virtualizes); 1 if the host also runs server roles | Unlimited |
| Storage Spaces Direct | No | Yes |
| Storage Replica | No | Yes |
| Software-defined networking | Limited | Full |
| Shielded VMs / host guarding | No | Yes |
| Typical use | Small office, single role, light VMs | Private cloud, dense Hyper-V, S2D |
| Licensing basis | Per core, plus CALs | Per core, plus CALs |

## The two numbers people mix up

1. **Cores, not sockets.** A 16-core host needs 16 cores of licence (subject to minimums and the agreement). Two 8-core CPUs are not “two licences” by themselves.
2. **OSE vs CAL.** The OSE count is how many server instances the host licence covers. A CAL is how users/devices access the services. They are different meters.

## Evaluation lifecycle

- Windows Server 2025 Evaluation is valid for **180 days**.
- It is not a production licence and cannot be “activated permanently”.
- In the lab: install → snapshot → clone → record `expiresAt` → rebuild from the template before expiry.
- If you need a longer-lived lab, use a licensed edition you actually own, or rebuild on a schedule.

## What to check before you install

- Is the workload Standard-sized or Datacenter-sized?
- How many cores does the host expose to the VM?
- Will the host run other roles, or only virtualize?
- Do you need S2D/Storage Replica, or just a file share?
- Who accesses the server, and what CAL model applies?

## Hardware side of a licence decision

- [Server hardware and Windows Server](https://windows.homes/en/hardware/homelab/server-hardware/) — ECC, NIC teaming, iSCSI, IPMI and where consumer hardware stops being adequate.
- [Used servers for a Windows homelab](https://windows.homes/en/hardware/homelab/used-server/) — what to check before buying, and where licensing bites.

## Sources

- [Microsoft Learn — Windows Server release information](https://learn.microsoft.com/en-us/windows-server/get-started/windows-server-release-info)
- [Microsoft Learn — Choose a Windows Server edition](https://learn.microsoft.com/en-us/training/modules/select-windows-server-editions-servicing-options-activation/2-choose-windows-server-edition)
- [Microsoft Evaluation Center — Windows Server 2025](https://www.microsoft.com/en-us/evalcenter/download-windows-server-2025)

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Source: https://windows.homes/en/server/start/editions-licensing/