Windows Server and CAL Licences: A Complete Guide

Setting up a Windows Server environment? You will need two things: a Windows Server licence and Client Access Licences (CALs) for every user or device connecting to that server. Without CALs, your server setup is not properly licensed — even if the server itself is activated.

This guide explains what CALs are, the four types available, how to calculate how many you need, and where to buy them at the best price.

What Are Client Access Licences (CALs)?

A Client Access Licence (CAL) is a licence that grants the right to access a Windows Server. Microsoft requires a CAL for every user or device that connects to any Windows Server service — including file shares, Active Directory, Exchange, SQL databases, print servers, and Remote Desktop.

Key point: A Windows Server licence on its own only covers the server software. Without CALs, users and devices cannot legally access that server. Think of it this way: the server licence is the building, and CALs are the entry passes.

The 4 Types of CALs

1. User CAL

A User CAL is assigned to a specific person. That person can access the server from any number of devices — desktop, laptop, tablet, or phone.

Licensed to: One named user
Devices: Unlimited devices per user
Best for: Companies where employees use multiple devices (laptop + phone + tablet)
Example: 10 employees × 1 User CAL each = 10 User CALs, regardless of how many devices they use

2. Device CAL

A Device CAL is assigned to a specific device. Any number of users can access the server from that device.

Licensed to: One specific device
Users: Unlimited users per device
Best for: Shared workstations, kiosks, reception desks, or factory terminals where multiple people use the same computer
Example: 5 shared computers used by 20 staff = only 5 Device CALs needed

3. RDS User CAL (Remote Desktop Services)

An RDS User CAL is required when a user connects to a Windows Server via Remote Desktop. This is in addition to a regular User or Device CAL.

Required for: Remote Desktop connections (RDP)
Licensed to: One named user
Note: You need BOTH a standard CAL AND an RDS CAL for remote desktop access

4. RDS Device CAL (Remote Desktop Services)

Same as above, but assigned to a specific device rather than a user.

Required for: Remote Desktop connections from a specific device
Licensed to: One specific device
Best for: Thin clients or shared terminals used for RDP

User CAL vs Device CAL: Which Do You Need?

The choice between User and Device CALs depends on your ratio of users to devices:

Scenario	Best CAL Type	Why
10 employees, each with a laptop + phone	User CAL	10 User CALs vs 20 Device CALs — saves money
5 shared computers used by 20 staff in shifts	Device CAL	5 Device CALs vs 20 User CALs — saves money
50 employees, each with one desktop	Either	50 CALs either way — same cost
Remote workforce accessing server via RDP	User CAL + RDS User CAL	Users work from personal devices at home

Rule of thumb: If you have more devices than users, choose User CALs. If you have more users than devices, choose Device CALs.

RDS CALs: When Do You Need Them?

You need RDS CALs whenever users access a Windows Server through Remote Desktop Services (formerly Terminal Services). Common scenarios:

Remote workers connecting to a company server via RDP
Thin client setups where desktops run on the server
Application hosting — running apps on the server that users access remotely
Virtual desktops hosted on Windows Server

Important: RDS CALs are in addition to regular User or Device CALs. A user connecting via Remote Desktop needs: 1 User CAL + 1 RDS User CAL.

CAL Types at a Glance

CAL Type	Licensed To	Access From	Needed For
User CAL	Named user	Any device	All server access
Device CAL	Specific device	Any user on that device	All server access
RDS User CAL	Named user	Any device (via RDP)	Remote Desktop only
RDS Device CAL	Specific device	Any user (via RDP)	Remote Desktop only

How Many CALs Do You Need?

Calculate your CAL requirements with these steps:

Count users OR devices (whichever is fewer = cheaper option)
Every user/device that accesses the server needs one standard CAL
Add RDS CALs for anyone using Remote Desktop
Match the CAL version to your server version (or newer — see compatibility below)

Example: Small Business with 15 Employees

15 employees, each with 1 laptop → 15 User CALs
5 of them work remotely via RDP → 5 RDS User CALs
Running Windows Server 2022 → need Windows Server 2022 CALs

CAL Version Compatibility

A CAL must be the same version or newer than the Windows Server it connects to:

Windows Server 2022 CAL → works with Server 2022, 2019, 2016
Windows Server 2019 CAL → works with Server 2019, 2016 (NOT 2022)
Windows Server 2025 CAL → works with all versions

Tip: Buying the latest CAL version gives you the most flexibility if you upgrade your server later.

Windows Server CAL Pricing at Licendi

Licendi offers genuine EU-legal CALs at competitive prices. All licences include instant digital delivery and lifetime warranty.

Server Licences

Windows Server 2025 Standard — from €306.60
Windows Server 2022 Standard — from €239.66
Windows Server 2019 Standard — from €177.68

Client Access Licences

Windows Server 2025 CAL — from €148.75
Windows Server 2022 CAL — €140.49
Windows Server 2019 CAL — €104.16

All licences are 100% EU-legal under the UsedSoft ruling, backed by Trustpilot 4.8★ (220+ reviews), and supported by our personal customer service team.

➤ Browse all Windows Server products at Licendi

Frequently Asked Questions

Do I need CALs if I only have one server?

Yes. CALs are required regardless of how many servers you have. Every user or device that accesses any Windows Server needs a CAL. The exception is Windows Server Essentials, which includes CALs for up to 25 users and 50 devices.

Can I mix User CALs and Device CALs?

Yes, you can use a combination of User and Device CALs in the same environment. This is common in organisations with both dedicated workstations and mobile employees.

What happens if I do not have enough CALs?

Without sufficient CALs, your organisation is not properly licensed, which puts you at risk during a Microsoft audit. Windows Server does not technically enforce CAL limits (users can still connect), but you are legally required to have the correct number.

Do CALs expire?

No. CALs are perpetual licences — they do not expire. However, they must match the server version (same version or newer). If you upgrade your server from 2019 to 2022, you need 2022 CALs (or newer).

Does Windows Server Essentials include CALs?

Yes. Windows Server Essentials includes CALs for up to 25 users and 50 devices at no extra cost. This makes it the most affordable option for very small businesses. Windows Server 2022 Essentials is available at Licendi for €412.40.