RDS vs User CAL

kentr 21 Reputation points

I have an environment of 4 ESXi hosts, 2 CPUs each, 22 cores per CPU. We have 10 VMs that serve as end user RDS terminals with about 400 active users logged in each day.

The best I understand from MS, the CAL setup needs to be:

~450 user CALs, and ~450 RDS CALS?

Or is it better to do device CALs and device RDS cals? Or do I just need RDS cals? I've been looking around on this and think I have just been confusing myself.

Remote Desktop
Remote Desktop
A Microsoft app that connects remotely to computers and to virtual apps and desktops.
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  1. TP 83,721 Reputation points


    If you choose per user, then you need to have enough Windows Server User CALs and RDS User CALs to cover each unique user (human). So if you have 450 unique humans that connect, then 450 of each type of CAL would be correct. Note it doesn't matter how many active users log in from a licensing perspective. Each user that connects, even one time, needs a Windows Server User CAL and RDS User CAL dedicated to them.

    The choice between Per User or Per Device usually comes down to which you have more of. If you have many more users (humans) than devices, then usually Per Device makes more sense since it will cost less. Conversely, if you have many more devices than humans, then Per User will cost less.

    Per User is the most common, since often users will connect from the Office, or their laptop, or their home, or a kiosk using the web client, etc., so the number of devices is much higher than the number of users.


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  1. Michael Durkan 12,196 Reputation points MVP


    Windows CALs are for either user or device server access. RDS CALs are for remote desktop application server access.

    Info on windows CALS here:


    Info on RDS CALS here:


    One of the things you need to be aware of is that RDS CALs are asigned to users on connection to the RDS environment, and stay assigned for a period of 30 days. Only if not used are the released back into the pool. You will need an RD Licensing Server to manage your RDS CALs.

    You could use this tool to assess the Device CAL requirements based on your environment:


    Hope this helps,


    Michael Durkan

    • If the reply was helpful please upvote and/or accept as answer as this helps others in the community with similar questions. Thanks!
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  2. kentr 21 Reputation points

    Ok, so for us, user is the way to go (as yes, they connect from laptops, desktops, home laptops, macs, etc). Ok, User AND RDS, got it! Thanks everyone!

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