RDS CAL Explained: User vs Device CALs for Windows Server 2025

Published: October 24, 2026 | Updated: October 24, 2026

Last reviewed: October 2026. Microsoft can change prerequisites and Remote Desktop licensing guidance, so confirm current requirements before changing a production environment.

An RDS CAL (Remote Desktop Services Client Access License) is the license that lets a user or a device connect to a Windows Server session host for remote desktops or RemoteApp programs. Buying Windows Server itself does not cover those connections, and simply enabling Remote Desktop on a server does not turn it into a multi-user platform.

The questions most teams actually ask are practical. Should you buy User CALs or Device CALs? Will your Windows Server 2022 CALs work on a new Windows Server 2025 host? What happens when the 120-day grace period runs out? Do you need a license server if you only have five users?

This guide explains how RDS CAL licensing works, how to choose between the two CAL types, which versions are compatible, and how to install and assign the licenses, with practical checks and beginner-friendly explanations along the way.

RDS CAL: Quick Answer

RDS CAL in brief: every user or device that connects to a Remote Desktop Session Host needs an RDS CAL once the 120-day grace period ends. The CALs are installed on an activated Remote Desktop license server, which hands them out to connecting clients.

Quick answer: Choose User CALs when each person has their own devices and works from several of them. Choose Device CALs when several people share the same computers, for example on shifts, or when your servers are in a workgroup rather than an Active Directory domain.

The CAL version must be the same as, or newer than, the session host version. Windows Server 2025 CALs work on Windows Server 2025 and earlier session hosts, but Windows Server 2022 CALs cannot be used to connect to a Windows Server 2025 host.

RDS CAL at a Glance

Here are the core facts in one place:

Most RDS licensing decisions come down to three questions: who connects, from which devices, and which Windows Server version the session hosts run. Get those right and the rest is mostly administration.

What Is an RDS CAL?

A Client Access License, or CAL, is a license that grants a user or device the right to access a server’s services. It is not software and it is not a product key for the server itself.

An RDS CAL specifically covers access to Remote Desktop Services. That includes full session-based desktops, where several people sign in to the same server at once, and RemoteApp programs, where a single application runs on the server but appears in a window on the user’s own PC.

Microsoft states that when a user or device connects to a session host, the session host decides whether a license is needed and, if so, requests one from a Remote Desktop license server. The license server installs, issues and tracks the CALs.

The server operating system is licensed separately. For a new deployment, that usually means a host license such as Windows Server 2025 Standard, which covers one physical server and includes rights for two virtual machines, plus your client licenses on top. You can browse the full range of server licenses in the Windows Server category.

Why RDS CAL Licensing Matters

Remote Desktop Services is one area where Windows Server actively enforces licensing. Once the grace period ends, clients that cannot get a valid license are refused a session, which tends to be noticed at 9:00 on a Monday morning.

Getting the licensing right early brings a few concrete benefits:

• No surprise sign-in failures when the 120-day grace period expires
• The right CAL type for how people really work, so you are not paying for two models
• Version-matched CALs that survive a future host upgrade
• Clean reporting if your licensing is ever reviewed
• Fewer support tickets blaming the network for what is really a licensing issue

What an RDS Deployment Needs

The license itself is only one part of the picture. A working session-based deployment typically includes these pieces:

These roles can all sit on one server in a small office, or be spread across several in a larger organization. In a small setup, one Windows Server may be wearing several hats at once, which is fine as long as it is sized for the load.

IMPORTANT: RDS hosts often carry line-of-business applications and sensitive data. If the server is business-critical, involve an experienced Windows Server administrator before changing roles or licensing settings in production.

RDS CAL Types: User vs Device

Microsoft offers two CAL types, and the right one depends on how people and devices connect to your session hosts.

Quick answer: Choose a User CAL for staff who move between a laptop, a home PC and a tablet. Choose a Device CAL if several people share the same computers.

The table shows an important nuance. Per User CALs are not hard-enforced the way Per Device CALs are, so Microsoft makes it the administrator’s responsibility to ensure every user has a valid license. The Remote Desktop Licensing Manager can generate reports on Per User CALs to help you check.

This guide focuses on how RDS CAL licensing works in general. If you are planning a server refresh at the same time, our guide to Windows Server 2016 End of Support covers the upgrade timing in more detail.

When User CALs Make Sense

User CALs follow the person. One licensed user can connect from an office desktop, a laptop at home and a phone without needing three licenses.

They suit office staff, hybrid workers and consultants who switch between devices. The main limitation is that your session hosts must be joined to an Active Directory domain, because Per User CALs cannot be tracked in a workgroup.

When Device CALs Make Sense

Device CALs follow the hardware. One licensed device can be used by any number of people, which makes them the natural fit for call centers, clinics, classrooms, factory floors and reception desks with rotating shifts.

Microsoft’s own example is an environment with two or more shifts of workers using the same computers. Device CALs are also the only option when the session host and license server sit in a workgroup, which is common in very small offices without a domain controller.

RDS CAL Version Compatibility

This is where many purchases go wrong. Microsoft states that you can use later CAL versions to access earlier versions of Windows Server, but you cannot use earlier CALs to access later versions.

Here is how the CAL version lines up with the session host version:

The license server has its own rule. CALs can only be installed on a license server running the same Windows Server version as the CALs, or a later one. A Windows Server 2025 license server can hold 2016, 2019, 2022 and 2025 CALs, while a Windows Server 2022 license server cannot hold 2025 CALs.

If there is any chance you will move to Windows Server 2025 hosts in the next few years, buying 2025 RDS CALs now avoids paying for the same seats twice.

Can You Use Windows Server 2022 RDS CALs on Windows Server 2025?

No. Windows Server 2022 CALs cannot be used to connect to a session host running Windows Server 2025. You would need Windows Server 2025 CALs for those users or devices.

The reverse works. If your hosts still run Windows Server 2022, the User CAL for Windows Server 2022 RDS remains a valid choice, but it will not carry forward to a 2025 host.

Do You Need an RDS CAL for Admin Access?

No, not for basic administration. Windows Server allows two concurrent Remote Desktop connections for administrative purposes without additional licenses.

Once you need more than two administrative connections, or you want ordinary users to work on the server, you must install the RD Session Host role and license those connections with CALs. Using the admin connections as a free two-seat terminal server for staff is not what they are for.

What Happens When the RDS Grace Period Ends?

Connections are refused. Microsoft provides a licensing grace period of 120 days during which no license server is required, and once it ends, clients must have a valid CAL issued by a license server before they can sign in to a remote session.

The grace period is meant for setup and testing, not as a trial to rely on. Plan to have the license server activated, CALs installed and the licensing mode configured well before day 120.

How to Install and Assign RDS CALs

The process has four parts: install the license server role, activate it, install the CALs and point your session hosts at the license server.

Step 1: Install the RD Licensing Role

Add the Remote Desktop Licensing role service through Server Manager on the server that will act as your license server. In a small deployment this can be the session host itself.

Step 2: Activate the License Server

Open RD Licensing Manager and select Action → Activate Server. Microsoft offers three connection methods:

• Automatic connection (recommended), over outbound TCP port 443
• Web Browser, when the server has no internet access but another computer does
• Telephone, when there is no internet access at all

License server activation is a separate process from Windows or Office product activation. Bcdkey’s Get Confirmation ID tool is designed for Windows and Office phone activation, not for activating an RD license server.

Step 3: Install the RDS CALs

Microsoft’s install steps are short:

1. Open Remote Desktop Licensing Manager.
2. Right-click the license server name and select Install licenses.
3. Select the license program you purchased the CALs through, then select Next.
4. Enter the license code or agreement number.
5. Select the product version, license type and number of licenses.
6. Select Finish once the Microsoft Clearinghouse validates the licenses.

Make sure the product version and license type match what you bought. A Per User pack installed while your hosts are set to Per Device will sit unused, quietly earning nothing.

Step 4: Configure the Licensing Mode

For deployments with an RD Connection Broker, open Server Manager and go to Remote Desktop Services → Overview → Edit Deployment Properties → RD Licensing. Select Per User or Per Device, then add your license server.

For session hosts without a Connection Broker, use Group Policy at this path:

Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Licensing

Enable both of these policies:

• Use the specified Remote Desktop license servers
• Set the Remote Desktop licensing mode

Microsoft also notes that workgroup session hosts patched for CVE-2024-38099 need credentials for the license server stored for the NT AUTHORITY\NETWORK SERVICE account. The command looks like this:

cmdkey /add:LICENSESERVER /user:LICENSESERVER\username /pass

READY CHECK: Before the grace period ends, confirm in RD Licensing Manager that CALs are being issued and that the licensing mode matches the CAL type you installed.

Need installation help for the server itself? See Bcdkey’s guide on how to download, install and activate Windows Server 2022 Standard.

7 RDS CAL Rules Worth Remembering

If you only keep one section of this guide, keep this one:

1. Every user or device connecting to an RD Session Host needs a CAL after the 120-day grace period.
2. Match the CAL type to how people work: Per User for named staff, Per Device for shared machines.
3. Workgroup servers must use Per Device CALs.
4. The CAL version must be equal to or newer than the session host version.
5. The license server must run the same or a newer Windows Server version than the CALs it holds.
6. The licensing mode on the hosts must match the CAL type installed on the license server.
7. RDS CALs sit on top of the Windows Server host license, and Windows Server CALs are generally required as well.

Common RDS CAL Mistakes

A handful of mistakes account for most RDS licensing problems.

1. Buying Older CALs for a Newer Host

Windows Server 2022 CALs will not license a Windows Server 2025 session host, so check the host version before you order.

2. Choosing User CALs in a Workgroup

Per User CALs cannot be tracked without Active Directory, so workgroup deployments should use Device CALs.

3. Leaving the Licensing Mode Unset

Installed CALs do nothing until the session hosts are told which license server and licensing mode to use.

4. Treating the Grace Period as a Trial

The 120 days are for deployment and testing, and sign-ins stop once they end without a working license server.

5. Forgetting the License Server Version

A Windows Server 2022 license server cannot hold 2025 CALs, so upgrade the license server first when you move to 2025 CALs.

6. Counting Devices When You Meant Users

If ten staff each use a desktop and a laptop, ten User CALs usually cover them more neatly than twenty Device CALs.

Is an RDS CAL Right for You?

Not everyone who wants “remote desktop” needs Remote Desktop Services. Connecting from home to your own single Windows 11 Pro PC uses the built-in Remote Desktop feature, which is a different thing entirely. For that scenario, our Windows 11 Home vs Pro comparison explains which edition can host a Remote Desktop connection.

RDS CAL licensing is generally the right choice when:

• Several people need to work on the same Windows Server at the same time
• You publish line-of-business applications as RemoteApp programs
• Staff use thin clients or older PCs that cannot run the software locally
• You need more than two concurrent connections to a server
• You want applications and data to stay on the server rather than on endpoints

You may need more preparation when:

• Your session hosts are not yet joined to a domain but you want User CALs
• You are mixing Windows Server versions across hosts and license servers
• Applications have their own licensing rules for multi-user servers
• Users connect from outside the office and you have not planned RD Gateway

Office and other applications have their own rules for shared and multi-user servers. An RDS CAL licenses the connection, not the software users run inside the session.

Which RDS CAL Should You Buy?

For new Windows Server 2025 hosts, the User CAL for Windows Server 2025 RDS comes in 5, 10, 20 or 50-user packs and lets each licensed person connect from any number of devices. It requires domain-joined session hosts.

For shared computers or workgroup servers, the Device CAL for Windows Server 2025 RDS comes in 5, 10, 20 or 50-device packs and covers any number of users on each licensed device. Both 2025 packs also work on Windows Server 2022, 2019 and 2016 session hosts, as long as the license server runs Windows Server 2025.

If you are staying on Windows Server 2022 for the foreseeable future, the Device CAL for Windows Server 2022 RDS is a reasonable fit, with the version limits explained above. You do not need the newest CALs simply because they exist, but you do need them before a 2025 host goes live.

All options are listed in the Remote Desktop Services CAL category. Organizations licensing larger numbers of users can ask about volume purchasing through the Bcdkey B2B wholesale program.

Explore More Windows Server Guides

These Bcdkey resources cover the questions that usually come next:

For the official reference, Microsoft’s guide to licensing your RDS deployment with client access licenses provides the full compatibility tables. Microsoft Learn also documents how to install RDS client access licenses and how to license Remote Desktop session hosts.

Final Thoughts

RDS CAL licensing is not really about collecting license codes. It is about matching the license to how people actually connect, and to the Windows Server version they connect to.

The essentials are short: every user or device needs a CAL after the 120-day grace period, User CALs need Active Directory, Device CALs suit shared machines, and the CAL version must be equal to or newer than the session host.

For most new deployments, the simplest path is Windows Server 2025 CALs on a Windows Server 2025 license server, because they cover both current and older hosts. Teams staying on Windows Server 2022 can keep using 2022 CALs, with a clear plan for the upgrade.

Before you order, write down three numbers: how many people connect, how many devices they use, and which Windows Server version your hosts run. That list usually makes the choice for you.

When you are ready to choose a CAL type, compare the Remote Desktop Services CAL range on Bcdkey.

FAQ About RDS CAL Explained: User vs Device CALs for Windows Server 2025

What is an RDS CAL?

An RDS CAL is a Remote Desktop Services Client Access License. It grants one user or one device the right to connect to a Windows Server RD Session Host for remote desktops or RemoteApp programs.

Do I need an RDS CAL for every user?

Yes, after the 120-day grace period, every connecting user or device needs a client access license. You choose whether to license per user or per device, not both for the same connection.

Can I use Windows Server 2022 RDS CALs with Windows Server 2025?

No. Windows Server 2022 CALs cannot license connections to a Windows Server 2025 session host, although Windows Server 2025 CALs can license 2022 and older hosts.

Can I use User CALs in a workgroup?

No. Per User CALs cannot be tracked in a workgroup, so session hosts that are not joined to Active Directory must use Per Device CALs.

How long is the RDS grace period?

The RDS licensing grace period is 120 days. After it ends, clients need a valid CAL issued by a license server before they can sign in to a remote session.

Do administrators need RDS CALs?

Normally, no. Windows Server allows two concurrent remote connections for administration without these licenses, but more connections or regular user sessions require the RD Session Host role and CALs.

Can I install 2025 RDS CALs on a Windows Server 2022 license server?

No. CALs must be installed on a license server running the same Windows Server version or later, so 2025 CALs need a Windows Server 2025 license server.

Is an RDS CAL the same as a Windows Server CAL?

No. A Windows Server CAL covers access to the server itself, while an RDS CAL covers Remote Desktop Services sessions, and most licensing agreements expect both for RDS users.

Does an RDS CAL license Office inside the session?

No. An RDS CAL licenses the remote connection only, and applications such as Office have their own rules for use on shared or multi-user servers.

Can I switch from User CALs to Device CALs later?

Yes, you can change the licensing mode on your session hosts at any time, but the license server must have CALs of the matching type available before the change, or connections will fail once the grace period has ended.