Measure from the screen to the chair furthest away.
White numbers will be sufficient for your room. The marked one is the smallest that will work.
Here a standard screen won't reach far enough. Two screens, a projector or a LED wall are often better choices. We help you calculate.
Get a recommendation for your roomInch rule for screens in 16:9 format. The height of the image should be at least one sixth of the distance for conversations and one quarter for details.