If you're setting up a Windows Server, one of the first licensing decisions you'll need to make is whether to choose a User CAL or a Device CAL. While the names may sound technical, the difference is straightforward.

A User CAL is assigned to one person, allowing that individual to access the server from multiple devices, such as a desktop, laptop or home computer.

A Device CAL is assigned to one device, allowing anyone using that licensed device to access the server.

The right choice depends on how your employees or users access the server. If people regularly work from multiple devices, a User CAL is usually the better option. If several people share the same computer, a Device CAL is typically the better fit.

If you plan to use Remote Desktop Services (RDS), you may also need additional RDS licensing depending on your deployment.

So, Choose a User CAL when access follows the person, and choose a Device CAL when access follows the device.

What Is a Microsoft User CAL?

A Microsoft User CAL (Client Access License) is assigned to one person rather than a specific device. This means the licensed user can access Windows Server from multiple devices, as long as they are the authorized user.

For example, an employee may use an office desktop during the day, a laptop while travelling and a home computer when working remotely. With a User CAL, that individual is licensed to access the server from each of those devices.

User CALs are a good choice for businesses where employees regularly switch between devices or work from different locations.

Example:

Sarah works in a marketing team. She uses a desktop in the office, a laptop for meetings and occasionally works from home using her personal computer. Since the server access follows Sarah rather than a single device, a User CAL is the more suitable option.

So, User CALs are best suited for businesses where employees access Windows Server from multiple devices.

What Is a Microsoft Device CAL?

A Microsoft Device CAL (Client Access License) is assigned to one device rather than a specific user. This means anyone using that licensed device can access Windows Server, making it a practical choice for shared computers.

Device CALs are commonly used in workplaces where multiple employees use the same computer, such as warehouses, retail stores, factories, schools or hospitals.

Example:

A warehouse has one computer at the shipping desk that is used by employees across different shifts. Since the server is always accessed through the same shared computer, a Device CAL for that computer is usually the more suitable option.

So, Device CALs are best suited for businesses where multiple people share the same computers to access Windows Server.

User CAL vs Device CAL: Quick Comparison

The main difference is whether the license is assigned to a person or to a device. This quick comparison can help you see which option better matches the way your business accesses Windows Server.

Finally, Choose a User CAL when access follows the employee, and choose a Device CAL when access is tied to a shared computer.

Which Microsoft CAL Should You Choose?

Choosing between a User CAL and a Device CAL depends on how people access your Windows Server rather than the size of your business. The right choice is based on your working environment and how employees connect to the server.

Choose a User CAL if

A User CAL is usually the better choice when:

✓ Employees use multiple devices, such as a desktop, laptop and home computer.
✓ Your team works remotely or follows a hybrid work model.
✓ Each employee has their own dedicated computer.
✓ Server access follows the individual rather than a specific device.

Example:
A marketing agency has 20 employees. Each employee uses an office desktop and a laptop for remote work. Since every employee accesses the server from multiple devices, User CALs are typically the better choice.

Choose a Device CAL if

A Device CAL is usually the better choice when:

✓ Multiple employees share the same computer.
✓ Employees work in shifts.
✓ Computers stay in fixed locations.
✓ Server access always happens through shared devices.

Example:
A warehouse has 30 employees working across different shifts using 10 shared computers. Since the server is accessed through the same devices, Device CALs are typically the more practical option.

Choose Both if Your Business Has Different Working Environments

Some organizations benefit from using both licensing models.

✓ Office employees use dedicated desktops and laptops, making User CALs a suitable choice.
✓ Warehouse or factory staff share shared workstations, making Device CALs a better fit.

This approach allows each department to use the licensing model that best matches how employees access Windows Server.

In short: Choose the licensing model that reflects how your employees actually access Windows Server. The right choice depends on how the server is used, not simply on the number of employees or computers.

Do You Need an RDS CAL Too?

A Windows Server CAL and an RDS CAL (Remote Desktop Services Client Access License) are not the same thing. A Windows Server CAL allows users or devices to access standard Windows Server services, while an RDS CAL is used when users connect to a Windows Server through Remote Desktop Services (RDS).

If your employees simply access shared files, printers or applications running on the server, a Windows Server CAL may be all that's required. However, if they log in to a remote desktop or use RemoteApp through RDS, additional RDS licensing may also be needed.

Example:

A company allows employees to work from home by connecting to their office desktops through Remote Desktop Services. In this case, the required Windows Server licensing alone may not be enough, and RDS CALs may also be required depending on the deployment.

So, If your users connect through Remote Desktop Services (RDS), check whether additional RDS CALs are required for your Windows Server environment.

Common Licensing Mistakes to Avoid

Choosing the right CAL is not just about the number of employees or computers. Understanding how your Windows Server is accessed can help you avoid common licensing mistakes.

✓ Choosing a User CAL when multiple employees share the same computers.

✓ Choosing a Device CAL when employees regularly access the server from different devices, such as office desktops, laptops and home computers.

✓ Confusing a Windows Server CAL with an RDS CAL. They serve different purposes, and Remote Desktop Services may require additional licensing.

✓ Purchasing licenses before reviewing how users or devices will actually access the Windows Server.

Before choosing a licensing model, take a moment to understand how your employees access Windows Server. Selecting the right CAL from the beginning can simplify license management and help avoid unnecessary costs.