The Microsoft Windows Evaluation Center allows you to test Microsoft products for free before purchasing a license. Available products for review include Windows 11, Windows 10 Enterprise, Windows Server 2019, Windows Server 2016, and Windows Server 2012 R2.

These are full-featured versions of operating systems with a pre-installed evaluation key. The trial period is 90 days for Windows 10 Enterprise and 180 days for all Windows Server versions.

After the trial period ends, the user must either purchase a license or stop using it. If the trial period is insufficient, Microsoft allows extending it using a special command.

To extend the evaluation period in Windows 10 Enterprise, run the following command in the command line: slmgr.vbs -rearm.
For Windows Server, use the command: slmgr /rearm.

The evaluation period for Windows Server can be extended up to 5 times, allowing the Evaluation version to be used for a total of up to 3 years (180 days × 6).

It is important to remember that according to the terms of use, evaluation versions cannot be used for commercial purposes.