Xbox One’s default screen size is 8.5" by 5.5". If you want to change the size of the Xbox One’s main screen, there are a few ways to do it. The first way is to use the Xbox One’s Settings app. In the Settings app, open the System settings and then select Display and Graphics. In Display and Graphics, select Change display size. In the Change display size dialog, enter a new size for the Xbox One’s main screen. The new size should be in inches or centimeters. The second way is to use a third-party application like UltraISO or WinRAR. These applications can help you change the Xbox One’s main screen size automatically. To use UltraISO or WinRAR, first create a shortcut to them on your desktop or in your Start menu. Then open UltraISO or WinRAR and click on its shortcut to open it in the Settings app of your Xbox One console. In Display and Graphics, select Change display size again and enter a new size for the Xbox One’s main screen (in inches or centimeters). If you want to keep using your old resolution for gaming on your Xbox One console, you can do that too by using an application like XSplit Gamecaster or Fraps Studio. These applications can help you capture gameplay videos at different resolutions so that you can still play at those resolutions on other devices like Playstation 4 or PC later on.