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Guide · Windows Server

RDS CALs: per user or per device, how many do you need?

By Baptiste Morin, technician at MAO Informatique Updated on Reading time: 4 min
Quick answer

An RDS CAL is the access licence for Windows Server Remote Desktop Services. It comes on top of the Windows Server CAL, is counted per user or per device, and must be the same version as the session host server or newer. Choose per-user CALs if everyone connects from several devices, per-device CALs if several people share the same workstation.

What an RDS CAL covers

Remote Desktop Services (RDS) let people work on the server remotely: a full desktop or published applications (management software, accounting, ERP), from the office, from home or from a tablet. Every user or device that uses them needs two licences: a Windows Server CAL, to access the server, and an RDS CAL, for Remote Desktop.

Per user or per device

Per-user RDS CALPer-device RDS CAL
What it allowsOne person, from as many devices as they likeOne device, used by as many people as needed
Suited toEmployees who connect from the office, home and a tabletShared machines: front desk, workshop, shift teams
You countPeopleMachines
Server outside a domain (workgroup)Not allowedOnly possible mode
Enforcement by the licence serverNo technical block, but the number of CALs remains a contractual obligationA CAL is assigned to each device

How to count: three cases

SituationThe right choiceQuantity
10 employees who each work on a PC and a laptop, in the office and from homePer user10 RDS CALs
3 reception workstations shared by 9 people working in shiftsPer device3 RDS CALs
15 employees, 15 fixed workstations, no access from any other deviceEither15 RDS CALs

The licensing mode is set for the whole deployment when there is a Connection Broker, otherwise on each session host server (through Group Policy). If you have both profiles, plan separate session hosts.

The version rule

Session host serverAccepted RDS CALs
Windows Server 20252025 RDS CALs
Windows Server 20222022 or 2025 RDS CALs
Windows Server 20192019, 2022 or 2025 RDS CALs
Windows Server 20162016 RDS CALs and later

The Remote Desktop licence server must itself be of a version equal to or higher than the CALs it issues. A migration to Windows Server 2025 therefore needs 2025 RDS CALs and a 2025 licence server.

What does not need an RDS CAL

  • Administration: Windows Server accepts two simultaneous remote connections reserved for administration, without RDS CALs. Beyond that, or for users doing their work, you need the Session Host role and RDS CALs.
  • Access to files or printers without Remote Desktop: only the Windows Server CAL is due.

Installing and activating RDS CALs

  1. Install the Remote Desktop Licensing role and activate it with Microsoft.
  2. Install the RDS CALs on that licence server.
  3. Point the session hosts to the licence server and set the mode (per user or per device).
  4. Check the configuration with the RD Licensing Diagnoser.

Without a licence server, the session host works during a 120-day grace period. After that, connections are refused: this is often when an incomplete setup is discovered.

Special cases

  • External users (customers, partners): one RDS CAL per external person or device, or an RDS External Connector licence, on top of the Windows Server External Connector.
  • Windows Server Essentials: the 2025 licence terms do not include Remote Desktop for users. For RDS you need Standard or Datacenter.
  • Windows Server 2025 pay-as-you-go (Azure Arc): it removes the need for Windows Server CALs for standard use, but RDS CALs are still due.

The most common mistakes

  • Buying RDS CALs without the Windows Server CALs that go with them.
  • Installing 2022 RDS CALs for a 2025 host: they are not accepted.
  • Choosing per-user mode on a server outside a domain.
  • Counting workstations when each employee connects from several devices.
  • Letting the 120-day grace period expire without a configured licence server.

At Licenciel

The RDS 2022, 50 users product covers 50 users on a 2022 or earlier host. For other quantities, for Windows Server 2025 or for a full project, request a quote. To work out CALs and RDS CALs: the Windows Server licence calculator.

Frequently asked questions

Does the RDS CAL replace the Windows Server CAL?
No, it comes on top: to use Remote Desktop, each user or device needs a Windows Server CAL and an RDS CAL.
Can per-user and per-device RDS CALs be mixed?
The mode is set for the deployment (with a Connection Broker) or for each session host. To have both, plan separate session hosts.
Is an RDS CAL needed to administer the server remotely?
No: two simultaneous connections reserved for administration are included, without RDS CALs.
Does a 2022 RDS CAL work on Windows Server 2025?
No. The RDS CAL must be the session host’s version or newer. A 2025 host needs 2025 RDS CALs.
What happens after 120 days without a licence server?
The grace period ends and the session host refuses new connections until a licence server with RDS CALs is configured.
Does the server block me if I exceed my number of per-user RDS CALs?
No, per-user mode is not technically enforced. But going beyond the number of CALs purchased is still a breach of the licence agreement.
Does Windows Server Essentials allow Remote Desktop?
Not for users: the Windows Server 2025 Essentials licence terms do not include Remote Desktop Services. You need the Standard or Datacenter edition.
How many RDS CALs for 10 remote employees?
If each person connects from several devices: 10 per-user RDS CALs, plus 10 Windows Server CALs.

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