Q: What is a CAL (Client Access License)?

This is a type of commercial software license. It is not a software product itself. A CAL is needed for each user or device that connects to the server to use its services, which include file sharing, printing, or authenticating against a domain controller. It is a license that allows a user or device to legally access server software services. Microsoft uses this model for their server products, such as Windows Server, Exchange Server, and SQL Server.

Q: What are the types of RDS CALs?

There are two types of RDS CALs: Per-User RDS CAL and Per-Device RDS CAL. The correct selection of one is determined by the way the users and devices of your organization connect to the server.

Q: What is a Per-User RDS CAL?

A Per-User RDS CAL is a license assigned to a specific user. It allows that user to connect to a Remote Desktop Services server from any number of devices. Companies with more devices than users find this model cost-effective. Users in an Active Directory (AD) domain environment can use Per-User CALs since they are assigned to a user in Active Directory.

Q: What is a Per-Device RDS CAL?

A Per-Device RDS CAL is a license assigned to a specific device. It allows any user who uses that device to connect to a Remote Desktop Services (RDS) server. This licensing model works well in environments like factories, call centers, hospitals, libraries, hotel kiosks, or school computer labs where multiple users share the same device.

Q: Can Per-Device RDS CALs be tracked from Licensing Manager?

Per-Device RDS CALs can be tracked from Licensing Manager. Per-User RDS CALs can be tracked only in the Active Directory environment, they cannot be tracked in a workgroup environment.

Q: Can I revoke RDS CALs?

Per-Device lets you revoke up to 20% of RDS CALs. This is not possible with Per-User.

Q: What are Temporary RDS CALs?

Temporary RDS CALs are part of the Per-Device RDS CAL licensing model. They are not a separate product to buy. Instead, they are temporary licenses issued by a Remote Desktop Licensing server. When a new device connects to an RD Session Host server in Per-Device licensing mode for the first time, the server checks with the RD Licensing server and provides a temporary RDS CAL to that device.

Question 1

What is a Remote Desktop Services (RDS) CAL?

Accepted Answer

An RDS CAL (Remote Desktop Services Client Access License) is a Microsoft license that gives a user or device the right to connect to a Windows Server running the Remote Desktop Session Host (RDSH) role. Every person or device that connects to a remote desktop session needs one. Without valid RDS CALs in place, remote desktop connections stop working once the server's built-in grace period expires. RDS CALs are available for Windows Server 2025, 2022, 2019, and 2016.

Question 2

Do I need both a Windows Server CAL and an RDS CAL?

Accepted Answer

Yes — this is one of the most common points of confusion. You need both licenses for each user or device connecting via Remote Desktop Services:

A Windows Server CAL covers basic access to the server's network services (file sharing, printing, Active Directory authentication).
An RDS CAL is an additional license required specifically for connecting to the server's graphical desktop or running applications through Remote Desktop Services.

One does not replace the other. If a user connects to your Windows Server 2025 via RDS, they need a Windows Server 2025 CAL and a Windows Server 2025 RDS CAL.

Question 3

Do I need both a Windows Server CAL and an RDS CAL?

Accepted Answer

This is a common point of confusion. You typically need both:

Windows Server CAL: Lets a user/device access the server network (File, Print, DNS).
RDS CAL: Specifically required when a user/device initiates a Remote Desktop session to interact with the graphical interface or run applications remotely.

If you are using Remote Desktop Services, you technically need an RDS CAL for each user or device.

Question 4

Is an RDS CAL the same as a Terminal Services CAL?

Accepted Answer

Yes. "Terminal Services CAL" is the older name used before Windows Server 2008 R2. When Microsoft rebranded Terminal Services to Remote Desktop Services, the license name changed too. An RDS CAL and a Terminal Services CAL refer to the same license type. If you see references to "TS CAL" in older documentation, it means the same thing as an RDS CAL.

Question 5

What is the difference between an RDS CAL and an RDS SAL?

Accepted Answer

An RDS CAL is a perpetual (one-time purchase) license. An RDS SAL (Subscriber Access License) is a monthly subscription alternative, typically available only through Microsoft service providers authorized to use SPLA (Services Provider License Agreement). For most organizations running their own servers, RDS CALs are the standard option. RDS SALs are primarily used by hosting providers offering RDS as a managed service.

Question 6

Do I need RDS CALs if I use Citrix or another third-party remote access solution?

Accepted Answer

Yes. If Citrix, Parallels RAS, or any other third-party solution connects users to a Windows Server running the RDSH role, RDS CALs are still required. The licensing requirement comes from Microsoft — it applies regardless of which software brokers the remote desktop connection. The third-party tool does not replace or include the RDS CAL.

Question 7

Do I need RDS CALs for VDI (Virtual Desktop Infrastructure)?

Accepted Answer

It depends on what you're virtualizing. If your VDI environment runs Windows Server desktops through the RDSH role, then yes — you need RDS CALs. If you're running Windows 10 or Windows 11 virtual desktops (without RDS), you do not need RDS CALs, but you will need Windows VDA (Virtual Desktop Access) licenses or eligible Microsoft 365 subscriptions instead. If you use RDS to deliver Windows client desktops, you may need both.

Question 8

Are RDS CALs a one-time purchase or a subscription?

Accepted Answer

Standard RDS CALs are perpetual licenses — you buy them once, and they remain valid indefinitely with no annual renewal or subscription fee. Microsoft also offers subscription-based alternatives (such as RDS User Subscription Licenses through CSP), but the standard CALs most organizations purchase are a one-time cost.

Question 9

Are RDS CALs backward compatible?

Accepted Answer

Yes. Newer RDS CALs are always backward compatible with older Windows Server versions. For example:

A Windows Server 2025 RDS CAL works with Server 2025, 2022, 2019, and 2016 Session Hosts.
A Windows Server 2022 RDS CAL works with Server 2022, 2019, and 2016 Session Hosts.
A Windows Server 2019 RDS CAL works with Server 2019 and 2016 Session Hosts.
A Windows Server 2016 RDS CAL works with Server 2016, 2012 and 2008 Session Hosts.

However, the reverse is never true — older CALs cannot access a newer server. You cannot use a Windows Server 2019 RDS CAL to connect to a Windows Server 2025 Session Host. If you're planning a server upgrade, purchasing the latest CAL version gives you the most flexibility.

Question 10

Can I use Windows Server 2022 RDS CALs on a Windows Server 2025 Session Host?

Accepted Answer

No. Older CALs cannot be used with a newer server version. To connect to a Windows Server 2025 Session Host, you must have Windows Server 2025 RDS CALs. This is a hard Microsoft licensing requirement with no workaround.

Question 11

Can I install Windows Server 2025 RDS CALs on a Windows Server 2019 or 2022 License Server?

Accepted Answer

No. The RD Licensing Server must be running the same Windows Server version (or newer) as the CALs you want to install. A Windows Server 2019 License Server cannot recognize or install Windows Server 2025 RDS CALs — the option simply will not appear in the Install Licenses Wizard. You need to set up a new License Server running Windows Server 2025 (or later) to install 2025 CALs.

This is one of the most common issues administrators encounter when upgrading. View our activation guide →

Question 12

Do RDS CALs work with both Windows Server Standard and Datacenter editions?

Accepted Answer

Yes. RDS CALs are not edition-specific. The same CAL works with Standard, Datacenter, and Essentials editions of Windows Server. The only requirement is that the CAL version matches or exceeds the server version.

Question 13

Do I need separate RDS CALs for each server in a multi-server farm?

Accepted Answer

No. RDS CALs are not tied to a specific server. A single Per-User or Per-Device CAL covers access to any Remote Desktop Session Host in your environment, as long as all Session Hosts are running the same or an older Windows Server version as the CAL. You install your CALs on a central RD Licensing Server, and it manages issuance to all Session Hosts across your farm.

Question 14

Can I use the same RDS CALs across multiple servers?

Accepted Answer

Yes. Your RDS CALs are installed on a centralized RD Licensing Server, not on individual Session Hosts. When a user or device connects to any Session Host, that host contacts the Licensing Server to request a CAL. One pool of licenses serves your entire RDS infrastructure — there is no need to buy separate CALs for each server.

Question 15

What is a Per-User RDS CAL?

Accepted Answer

A Per-User RDS CAL is assigned to an individual person (through their Active Directory user account). Once licensed, that person can connect to the RDS environment from an unlimited number of devices — office desktop, laptop, tablet, phone, home computer — all covered under one license. This is the most popular option for organizations with remote and hybrid workers.

Question 16

What is a Per-Device RDS CAL?

Accepted Answer

A Per-Device RDS CAL is assigned to a specific physical device (computer, thin client, kiosk, or workstation). Once that device is licensed, any number of users can log in through it to access Remote Desktop Services. The license stays with the machine, not the person. This is the standard choice for shared workstations, shift-based environments, and labs.

Question 17

How do I decide between User CALs and Device CALs?

Accepted Answer

Count your users and count your devices, then license whichever number is smaller — that's the most cost-effective option.

Choose User CALs when your employees work from multiple devices (laptop + phone + home PC). One license per person covers everything. This fits most remote and hybrid teams.
Choose Device CALs when multiple people share a single workstation — shift workers in a call center, shared terminals in a warehouse, kiosk machines in a lobby, or lab computers in a classroom. One license per machine covers every user.

Not sure which fits your setup? Use our RDS CAL Calculator to get a personalized recommendation.

Question 18

How many RDS CALs do I need?

Accepted Answer

For Per-User CALs, count every unique person who will ever connect to your RDS environment — not just concurrent users. Even if someone only connects once a month, they need their own CAL.
For Per-Device CALs, count every physical device that will connect. If you have 30 workstations that access RDS, you need 30 Device CALs, regardless of how many people use those workstations.

Question 19

Can I mix User CALs and Device CALs on the same server?

Accepted Answer

Yes. Microsoft allows you to run both Per-User and Per-Device RDS CALs on the same Remote Desktop Session Host simultaneously. Many organizations use a mix to optimize costs — for example, Per-User CALs for remote workers who connect from multiple devices, and Per-Device CALs for shared kiosks or lab machines.

Question 20

Do Per-User CALs require Active Directory?

Accepted Answer

Yes. Per-User RDS CALs are tracked through Active Directory user accounts. While it is technically possible to install Per-User CALs in a workgroup (no domain controller), the license server cannot properly track user-based licensing in that configuration. If your Windows Server is in a workgroup without Active Directory, use Per-Device CALs instead.

Question 21

Can Per-Device CALs work in a workgroup environment (no Active Directory)?

Accepted Answer

Yes. Per-Device CALs function correctly in both workgroup and domain-joined environments. The license server tracks devices by their unique hardware identifier, which does not depend on Active Directory. This makes Per-Device the recommended choice when there is no domain controller present.

Question 22

Can I switch from Device CALs to User CALs (or vice versa)?

Accepted Answer

You cannot convert one CAL type into the other. If you need to change your licensing model, you would purchase new CALs of the desired type. However, since both types can run on the same server simultaneously, you can transition gradually — adding new CALs of the preferred type while the existing ones remain in use.

Question 23

What is the price of Windows Server RDS CALs?

Accepted Answer

Pricing depends on the server version, pack size, and CAL type. User and Device CALs are priced identically. Larger packs offer better per-CAL value. Pricing for Windows Server 2025, 2022, 2019, and 2016 versions varies. View all pricing and pack options →

Question 24

Does the RDS CAL include the Windows Server operating system license?

Accepted Answer

No. An RDS CAL is an access license only. It does not include the Windows Server operating system. You must have a separately licensed copy of Windows Server (Standard or Datacenter) with the RDSH role installed before RDS CALs can be deployed.

Question 25

What is an RD Licensing Server?

Accepted Answer

An RD Licensing Server is a Windows Server role that stores, issues, and tracks your RDS CALs. It must be installed and activated with the Microsoft Clearinghouse before it can issue licenses. When a user or device connects to a Session Host, the Session Host contacts the Licensing Server to check for a valid CAL before granting access.

Question 26

Can the RD Licensing Server and Session Host run on the same machine?

Accepted Answer

Yes. For small deployments or single-server setups, both the RD Session Host and RD Licensing roles can be installed on the same server. For larger environments with multiple Session Hosts, a dedicated (physical or virtual) Licensing Server is recommended for easier management.

Question 27

How do I activate the RD Licensing Server?

Accepted Answer

After installing the RD Licensing role through Server Manager, open the Remote Desktop Licensing Manager and right-click your server to begin activation. The Automatic Connection method contacts the Microsoft Clearinghouse over the internet. If your server has no internet access, use the Web Browser method instead, which lets you complete activation from a separate machine.

Step-by-step activation guide →

Question 28

How do I install RDS CALs on my license server?

Accepted Answer

Once the RD Licensing Server is activated, open the Remote Desktop Licensing Manager, right-click the server, and select Install Licenses. Enter your product key or License Agreement Number when prompted and follow the wizard. The CALs become available for issuance immediately after installation.

View installation guide →

Question 29

How do I configure the licensing mode (Per User or Per Device) on my Session Host?

Accepted Answer

The licensing mode must match the type of CALs you installed. Set this through Server Manager (Remote Desktop Services → Deployment Properties → RD Licensing) or through Group Policy (Computer Configuration → Administrative Templates → Windows Components → Remote Desktop Services → Remote Desktop Session Host → Licensing). A mismatch between the configured mode and installed CAL type will cause licensing errors.

View licensing mode configuration guide →

Question 30

Can one RD Licensing Server manage CALs for multiple Session Hosts?

Accepted Answer

Yes. A single RD Licensing Server can issue CALs to multiple Session Hosts across your network. This is the recommended setup — centralizing license management simplifies tracking. The Licensing Server can serve Session Hosts across Active Directory domains, forests, and workgroup environments.

Question 31

What is the RDS licensing grace period?

Accepted Answer

When you install the Remote Desktop Session Host role on a Windows Server, Microsoft provides a 120-day grace period. During this window, remote desktop connections work without an RD Licensing Server or any installed CALs. This gives you time to configure your licensing infrastructure. Once the 120 days expire, all remote connections (except the two built-in admin sessions) are blocked until valid CALs are deployed.

Question 32

What are temporary RDS CALs?

Accepted Answer

Temporary CALs are specific to the Per-Device licensing model. The first time a new device connects to the Session Host, the license server issues a temporary CAL valid for 52 to 89 days. When the device connects a second time, the license server upgrades it to a permanent Per-Device CAL (provided permanent CALs are available). If no permanent CALs are available, the temporary CAL continues to function until it expires.

Question 33

Does the Per-User model issue temporary CALs?

Accepted Answer

No. The Per-User model does not use temporary CALs. The license server grants a license directly from the available pool. Per-User CALs show an expiration date of 60 days after issuance, but they are automatically renewed each time the user connects, so the license remains active as long as the user is accessing the environment.

Question 34

Can I revoke an RDS CAL and reassign it?

Accepted Answer

It depends on the type:

Per-Device CALs: You can manually revoke up to 20% of your total issued CALs using the Remote Desktop Licensing Manager console. This is useful when a device is replaced or retired.
Per-User CALs: These cannot be manually revoked. They return to the available pool automatically when the user no longer connects.

Question 35

What happens to a Per-Device CAL when the device is retired or replaced?

Accepted Answer

If the device no longer connects to the RDS environment, its assigned CAL will expire naturally after 52–89 days and return to the available pool. If you need the license back immediately, you can use the 20% revocation allowance in the Licensing Manager.

Question 36

Can I transfer RDS CALs to a different license server?

Accepted Answer

Yes. If you are migrating to a new server, you can deactivate the old RD Licensing Server through the Licensing Manager (this contacts the Microsoft Clearinghouse), then install and activate your CAL keys on the new server. The process involves deactivating the old server, setting up and activating the new one, and reinstalling your license keys.

Question 37

How do I check how many RDS CALs are currently in use?

Accepted Answer

Open the Remote Desktop Licensing Manager on your RD Licensing Server. It shows the total number of installed CALs, how many have been issued, and how many remain available. For Per-Device CALs, you can see individual device assignments. For Per-User CALs in an Active Directory environment, you can generate reports showing which users have been issued licenses.

Question 38

Can I add more CALs to my server later?

Accepted Answer

Yes. You can purchase additional CAL packs at any time and install them on your existing RD Licensing Server alongside your current licenses. The new CALs are immediately added to your available pool. There is no limit to how many times you can expand your license count. Shop additional CAL packs →

Question 39

Do I need an RDS CAL for administrator connections?

Accepted Answer

No. Windows Server includes two concurrent administrative remote desktop sessions at no additional license cost. These are intended strictly for server management and maintenance tasks. However, if administrators use these sessions to run business applications (such as Office, an ERP system, or CRM software), RDS CALs are required for those sessions.

Question 40

Do I need an RDS CAL if I only use Remote Desktop to manage my server occasionally?

Accepted Answer

If you are only using the two built-in administrative sessions for server management, no RDS CAL is required. The moment you enable the Remote Desktop Session Host role to allow additional users or devices to connect — or if you use those admin sessions for running day-to-day business applications — RDS CALs become necessary.

Question 41

Do I need RDS CALs for external users (contractors, clients, partners)?

Accepted Answer

Yes. Any user connecting to your RDS environment requires an RDS CAL, regardless of whether they are an employee, contractor, client, or partner. There is no exemption for external users. If you have a large number of external users, Microsoft also offers an External Connector license as an alternative to individual CALs.

Question 42

Do I need RDS CALs in Microsoft Azure?

Accepted Answer

Yes. If you are running a Windows Server instance in Azure with the RDSH role enabled, you still need RDS CALs. Azure covers the base Windows Server license, but the RDS CAL is an additional requirement. Only Per-User RDS CALs with active Software Assurance can be used in Azure — Per-Device CALs are not permitted in cloud deployments.

Question 43

Can I use my existing RDS CALs in Azure?

Accepted Answer

Only if you have Per-User RDS CALs with active Software Assurance acquired through a Microsoft volume licensing program (such as an Enterprise Agreement). Standard retail RDS CALs or volume license CALs without Software Assurance cannot be used in Azure.

Question 44

Do I need RDS CALs for Azure Virtual Desktop (AVD)?

Accepted Answer

No. Azure Virtual Desktop (formerly Windows Virtual Desktop) runs on Windows 10/11 multi-session and does not use the Remote Desktop Session Host role on Windows Server. Because of this, RDS CALs are not required for AVD. AVD is licensed through Microsoft 365 or Windows Per-User subscriptions instead.

Question 45

What pack sizes are available for RDS CALs?

Accepted Answer

RDS CALs are sold in packs of 5, 10, 20, and 50 — available in both User and Device variants for Windows Server 2025, 2022, 2019, and 2016. You can purchase multiple packs and install them on the same license server. For example, two 50-User packs give you 100 User CALs.

Browse all available packs →

Question 46

Is this a digital or physical product?

Accepted Answer

>RDS CALs are a fully digital product. After purchase, you can download the license key instantly, you will also receive your product key and installation documentation via email — typically within minutes. There is no physical media or shipping involved.

Question 47

How fast will I receive my license after purchase?

Accepted Answer

You can download the license instantly upon successful payment, also your license key and documentation are delivered to your email address. Most customers receive everything within 5 minutes and can begin installation right away.

Question 48

Are RDS CALs region-locked?

Accepted Answer

No. RDS CALs are valid worldwide. A license purchased in any country can be activated and used on a server located anywhere else. There are no geographic restrictions.

Question 49

What do I receive with my purchase from RDS CAL Store?

Accepted Answer

You receive a PDF containing your license key, along with links to step-by-step installation guides and a video walkthrough. Free installation support is included with every order — our team can help you configure your license server and activate your CALs if needed.

Contact support →

Question 50

Why do my users see a "No Remote Desktop License Servers available" error?

Accepted Answer

This error means the Session Host cannot communicate with the RD Licensing Server. Check the following:

The RD Licensing Server is activated (look for a green checkmark in the Licensing Manager).
The Session Host is pointed to the correct Licensing Server (verify in Group Policy or Deployment Properties).
No firewall is blocking communication between the Session Host and the Licensing Server.
The Remote Desktop Licensing service is running on the Licensing Server.

Question 51

Why are users getting disconnected after 120 days?

Accepted Answer

The 120-day grace period has expired and no valid RDS CALs are available. To fix this, install and activate an RD Licensing Server, add your CALs, and configure your Session Host to point to it. Connections will resume immediately once valid CALs are in place.

View activation guide →

Question 52

The Licensing Manager shows "Not Activated" — what do I do?

Accepted Answer

Your RD Licensing Server needs to be activated with the Microsoft Clearinghouse before it can issue CALs. Open the Remote Desktop Licensing Manager, right-click your server name, and select Activate Server. If the automatic method fails (no internet), use the Web Browser or Telephone method as alternatives.

Question 53

I installed CALs but users still cannot connect — what went wrong?

Accepted Answer

Check three things:

Licensing mode mismatch: Make sure the licensing mode configured on the Session Host (Per User or Per Device) matches the type of CALs you installed. A mismatch causes connection failures.
Wrong license server: Verify the Session Host is pointed to the correct RD Licensing Server.
CAL availability: Open the Licensing Manager and confirm the CALs show as "Available" — not all issued or expired.

Question 54

The Install Licenses Wizard does not show my Windows Server version — why?

Accepted Answer

The RD Licensing Server can only install CALs for its own Windows Server version or older. If you're running the Licensing Server on Windows Server 2019, you will not see an option for Windows Server 2022 or 2025 CALs. The fix is to set up a new License Server running the same Windows Server version as the CALs you need to install.

Question 55

Can I reset the 120-day grace period?

Accepted Answer

Microsoft does not support or recommend resetting the grace period. It is a one-time window intended to give you time to set up licensing. The proper solution is to install valid RDS CALs before the grace period expires.

Frequently Asked Questions

Frequently Asked Questions

1. Understanding RDS CALs

2. User CAL vs. Device CAL

3. Compatibility & Version Requirements

4. How Much Do RDS CALs Cost?

5. Setup & Configuration

6. Grace Period & Temporary Licenses

7. Revoking, Transferring & Managing CALs

8. Administrator & Special Scenarios

9. Azure & Cloud Scenarios

10. Purchasing & Delivery

11. Troubleshooting