RDS CALs Explained: How Many Users Can Connect to Windows Server over RDP, and What the Licences Cost

Every Windows Server accepts two Remote Desktop connections without any extra licence. The question behind "RDS CALs explained" is what happens when a third person needs to sign in: which licence applies, who is allowed to sell it, what the 120-day grace period really means, and what it costs per month on a hosted server. This guide answers those questions with Microsoft's own rules and the prices that apply to a MassiveGRID Windows VPS, where RDP with two admin sessions is included and additional RDP user licences cost $8.90 per user per month.

The two sessions every Windows Server includes

Windows Server has supported two concurrent administrative Remote Desktop connections since Windows Server 2003, under what used to be called Remote Desktop for Administration. They need no Client Access Licence, no licensing server and no extra role; you enable Remote Desktop in Server Manager and two accounts can be signed in at once, each with its own desktop, profile and running programs. Microsoft intends them for administration, but there is no technical or licensing rule that says the two people cannot be using QuickBooks.

The limit shows up as the message "Another user is signed in. If you continue, they'll be disconnected" or "The number of connections to this computer is limited" when a third person connects. Disconnected sessions still count: a colleague who closed the RDP window without signing out is holding one of the two slots. On a MassiveGRID Windows VPS both sessions are included on every plan, which is enough for a small business owner and a bookkeeper, a developer and a tester, or one person who wants a safety net while changing firewall rules.

What changes with Remote Desktop Services

A third simultaneous user requires the Remote Desktop Session Host role, which turns the server into a multi-user terminal server, and each user or device that connects to it needs a Remote Desktop Services Client Access Licence (RDS CAL), issued by a Remote Desktop Licensing server. Installing the role gives you a licensing grace period of 120 days during which no licence server is needed; when it ends, clients without a valid RDS CAL can no longer sign in to a remote session. The grace period is for setting up licensing, not a free tier: Microsoft's terms require a CAL for every user or device from the first day of production use.

CALs are tied to the server version. An RDS CAL for Windows Server 2022 can connect to a session host running 2022 or earlier but not to one running Windows Server 2025, while a 2025 CAL works against any version. The licensing server itself must run the same or a newer version of Windows Server than the CALs installed on it.

Per-user or per-device?

Microsoft sells two kinds of RDS CAL, and you choose one mode per session host.

For a hosted server used by a team of knowledge workers the per-user model is almost always right: each person connects from a work laptop, a home PC and a phone, and that is one licence, not three. Per-device suits a warehouse or call centre where three shifts share one set of thin clients.

What RDS CALs cost on a hosted server

Hosting providers cannot sell you Microsoft's perpetual CALs. Under the Services Provider License Agreement they rent RDS Subscriber Access Licences by the month, one per named user, and report them to Microsoft. That is what MassiveGRID's additional RDP user licence at $8.90 per user per month is: it covers one person connecting to your Windows VPS from any device, on top of the two admin sessions included with the server. A team of five on one server therefore needs three additional licences, $26.70 a month, plus a server sized for five desktops.

If your organisation already owns RDS CALs, they can be used on a hosted server only through Microsoft's licence mobility rules, which require active Software Assurance; CALs bought without it stay on your own hardware. Mixing your own CALs with a provider's SPLA server is a licensing conversation to have with your Microsoft reseller before you order, not after an audit letter.

Sizing a server for several RDP users

Licences are the cheap part; the server has to carry the sessions. A reasonable planning figure for office work (browser, e-mail, Office, one or two business applications) is 1 vCPU and 2 GB of RAM per concurrent user, plus about 2 GB of RAM for Windows Server itself. Five concurrent users therefore want 4 to 6 vCPU and 12 GB of RAM; ten users want 8 vCPU and 24 GB.

Reserve the cores once there are more than two or three users. On a shared-CPU VPS a neighbour's load can make everyone's typing lag for a few seconds; a Windows Dedicated VPS reserves its vCPU and RAM so one user's spreadsheet recalculation is the only thing that can slow another user down, and its cores also make the per-vCPU Windows licence easier to budget. Store user profiles and documents on the server's NVMe volume, enable Windows Server's user profile disks or FSLogix if sign-in gets slow, and schedule reboots for a time nobody is connected.

Windows 10 and 11 Pro: one user at a time

Desktop Windows is licensed for a single interactive user. Windows 11 Pro accepts one Remote Desktop connection and signs out the console user when it does; it has no Remote Desktop Services role and no CALs. Tools that patch the system to allow several simultaneous RDP sessions on Windows 10 or 11, such as RDP Wrapper, break the licence terms and break again with every cumulative update. If more than one person needs to be signed in at once, the answer is Windows Server, which is why MassiveGRID's multi-user guides assume it; Windows 10 and 11 Pro templates are offered for single-user cases on the customer's own key.

Setting it up in practice

1. Order a Windows Server plan sized for the number of concurrent users and contact MassiveGRID support for the additional RDP user licences you need.
2. Install the Remote Desktop Services role with the Session Host and Licensing role services (a single server can hold both for a small team).
3. Point the session host at the licensing server and set the licensing mode to per user; the provider-supplied licences are installed on the licensing server.
4. Create a local or domain user for each person and add them to the Remote Desktop Users group. Admin accounts stay for administration.
5. Harden the server before the first user signs in: Network Level Authentication on, an account lockout policy, and ideally RDP moved off port 3389 or placed behind a VPN. The hardening checklist and the multiple RDP users guide cover every step with screenshots and commands.

Frequently Asked Questions

How many users can connect to Windows Server over RDP without CALs?

Two, using the administrative connections Windows Server includes by default. Both are included with every MassiveGRID Windows VPS. A third simultaneous user needs the Remote Desktop Session Host role and an RDS CAL per user or device.

What is the 120-day RDS grace period?

After the Remote Desktop Session Host role is installed, the server accepts connections for 120 days without a licensing server so you can set licensing up. It is not a free period under Microsoft's terms, which require a CAL for every user or device from the first day of use, and when it ends unlicensed users can no longer sign in.

How much do RDS CALs cost on a MassiveGRID Windows VPS?

$8.90 per additional user per month, rented under the provider's SPLA agreement and added on request. The two administrative sessions are included with the server at no extra cost.

Per-user or per-device RDS CAL: which should a small team choose?

Per-user, in nearly every hosted scenario. Each person connects from several devices, and a per-user CAL covers all of them. Per-device suits shared terminals used by several shifts.

Can I allow multiple RDP users on Windows 11 Pro?

No. Desktop Windows is licensed for one interactive user at a time and has no Remote Desktop Services role. Patches that enable concurrent sessions violate the licence terms. Use Windows Server for a multi-user desktop.