Remote Desktop Services (RDS) Client Access Licenses are one of the most misunderstood parts of Microsoft server licensing. Buy the wrong type and you're either overspending or out of compliance. This guide explains exactly what RDS CALs are, when you need them, and how to choose between User and Device licensing.
What Are RDS CALs?
An RDS CAL (Client Access License) gives a user or device the legal right to connect to a Windows Server running Remote Desktop Services. The server license alone doesn't cover remote connections — you need one CAL per user or per device that connects.
Important: RDS CALs are separate from Windows Server CALs. If you're running Remote Desktop Services, you need both a Windows Server CAL and an RDS CAL for each connection point.
User CALs vs Device CALs
| Factor | User CAL | Device CAL |
|---|---|---|
| Licensed to | A specific person | A specific device |
| Multiple devices? | Yes — one person, any device | No — one device, any user |
| Multiple users? | No — one person only | Yes — any user on that device |
| Best for | Employees with laptops + phones + tablets | Shared workstations, kiosks, labs |
| Remote workers | Ideal — covers all their devices | Not practical (would need CAL per device) |
| Shift workers sharing PCs | Expensive (CAL per worker) | Ideal (CAL per shared PC) |
Quick Decision Rule
- More devices than users? → User CALs (cheaper to license per person)
- More users than devices? → Device CALs (cheaper to license per shared device)
- Remote workforce? → User CALs (covers all their devices wherever they connect from)
How Many RDS CALs Do You Need?
Count your concurrent connection points:
- User CALs: One per person who will ever connect via RDS. If you have 20 employees who use Remote Desktop, you need 20 User CALs — even if they never all connect at the same time.
- Device CALs: One per device that connects to RDS. If you have 10 thin clients in a call center, you need 10 Device CALs — regardless of how many shift workers use them.
Note: You cannot mix User and Device CALs on the same RDS deployment. Pick one model and stick with it.
RDS CAL Versions: Match Your Server
RDS CALs must match or be newer than your Windows Server version:
| Windows Server Version | Compatible RDS CALs |
|---|---|
| Server 2019 | 2019, 2022, or 2025 CALs |
| Server 2022 | 2022 or 2025 CALs |
| Server 2025 | 2025 CALs only |
Pro tip: If you're planning to upgrade your server in the next year, buy the newer CAL version now — it covers both the current and future server.
Common RDS CAL Mistakes
- Forgetting RDS CALs entirely. A Windows Server license and Windows Server CALs don't include Remote Desktop access. RDS CALs are a separate, additional purchase. Without them, your remote connections aren't properly licensed.
- Mixing User and Device CALs. Microsoft doesn't allow mixing CAL types on one RDS deployment. Pick the model that fits your scenario and use it consistently.
- Using older CALs with newer servers. A 2019 RDS CAL doesn't work with Server 2022 or 2025. CALs must match or exceed the server version.
- Confusing RDS CALs with Windows Server CALs. You need both: a Windows Server CAL for general server access, plus an RDS CAL specifically for Remote Desktop connections.
- Not buying enough for future growth. It's cheaper to buy a 50-pack now than to add individual CALs later. Our bulk packs offer significant per-CAL savings.
Our RDS CAL Products
- Browse all RDS CAL packs
- Available in 50-User and 50-Device packs for Server 2019, 2022, and 2025
- Instant digital delivery — activate on your RDS License Server immediately
How to Activate RDS CALs
- Open Remote Desktop Licensing Manager on your RDS License Server
- Right-click your server and select Activate Server (if not already activated)
- Choose Install Licenses from the context menu
- Select your license program and enter your product key
- The CALs appear in the license pool and are automatically assigned to connecting users/devices
Need the server OS too? Check our Windows Server buying guide to pick the right version.
RDS CALs vs Microsoft 365 / Azure Virtual Desktop
| Factor | RDS CALs (On-Premises) | Azure Virtual Desktop |
|---|---|---|
| Infrastructure | Your own servers | Microsoft Azure cloud |
| Upfront cost | Server + CALs (one-time) | Monthly subscription |
| Ongoing cost | Hardware maintenance, power | Per-user/per-hour Azure billing |
| Data location | On your premises | Azure data centers |
| IT expertise | Required (server admin) | Moderate (Azure admin) |
| Best for | Fixed workforce, data sovereignty | Variable/seasonal workforce, cloud-first |
Why Buy from OfficeAndWin?
- Genuine Microsoft licenses — we're a Microsoft Partner
- Instant digital delivery — get your license key in minutes
- 21,000+ verified reviews — rated 4.71/5 on Judge.me
- Free activation support — we help with RDS License Server setup
Frequently Asked Questions
Do I need RDS CALs if I only use Remote Desktop to manage the server?
No. Windows Server includes 2 administrative Remote Desktop connections for server management. RDS CALs are only needed when you deploy Remote Desktop Services for end-user access (virtual desktops, RemoteApp, etc.).
Can I transfer RDS CALs to a different server?
User CALs are assigned to users, not servers, so they follow the person. Device CALs can be reassigned, but Microsoft's licensing terms limit how frequently. In practice, if you're migrating servers, your CALs carry over.
What happens if I run out of RDS CALs?
The RDS License Server enters a 120-day grace period for unlicensed connections. After that, users without a CAL assigned will be denied access. It's better to have a small surplus than to run short.
Are RDS CALs the same as Windows Server CALs?
No. Windows Server CALs cover general server access (file sharing, Active Directory, etc.). RDS CALs are an additional license specifically for Remote Desktop Services. You need both for RDS deployments.
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