You will need to consider a few things when selecting a screen size. This would help you in analyzing the best for your requirements. 

• The image size you’re looking for
• The type of screen surface required (fixed/pull-down screen)
• Distance between projector and screen 
• Preferred screen material (Glass/acrylic/fabric, etc)
• Lastly, select your desired brands and a budget

To determine the optimal display there are various factors taken into consideration such as the viewing distance, resolution, and human visual acuity. There’s a specific formula that is used to calculate optimal display. You can use a diagonal screen size calculator to calculate the diagonal.

As per Avixa standard – Display Image Size for 2D Content (DISCAS), the Diagonal Size (D) of the display is calculated using:

D = sqrt(W^2 + H^2)

W = AR * Image Height

H = L/Discas Constant * Image Height

In this formula

D: Diagonal Size of Display

W: Width of Display

H: Height of Display

AR: Aspect Ratio

L: Distance of last viewing person

Yes, you can head to the Projector Screen online screen size calculator that will guide you to select the best screen according to your inputs. However, you can also check out the same for multiple screens such as screens on the side and front walls.

All devices with screens employ an aspect ratio, which is the proportion between the height and breadth of a rectangular display. The ratio between a screen’s height and breadth is what is indicated by an aspect ratio screen size calculator rather than the size of the screen itself.