Room planning tool
Home Theater Screen Size Calculator
Enter a diagonal and screen shape to see the visible width and height before checking wall and frame clearance.
Calculate screen dimensions
Enter a diagonal and choose the screen shape. The result is the visible image area, not the outside frame.
How the screen calculation works
Let the aspect ratio be width divided by height. Height equals the diagonal divided by the square root of ratio squared plus one. Width equals that height multiplied by the ratio.
A 120-inch 16:9 image is about 104.6 inches wide and 58.8 inches high. A 2.39:1 image with the same diagonal is wider and shorter, so the wall area changes even though the advertised diagonal does not.
The result covers the visible image. Add the listed frame width and mounting clearance before deciding whether a model fits. If 120 inches suits the room, use the projector screen guide to compare fixed-frame, retractable and ambient-light-rejecting options.
Then check the viewing distance calculator, the projector screen guide and your projector's throw range before buying.
What the result does not include
- The outside frame, masking, mounting hardware or speaker clearance.
- Projector throw distance, which depends on the exact lens and zoom range.
- Whether the image feels comfortable from each seat in the room.
Screen size questions
Does the result include the screen frame?
No. Add the manufacturer's outside frame dimensions before checking wall clearance.
Why does aspect ratio change the width?
The diagonal stays fixed while the rectangle changes shape. A wider ratio produces more width and less height.
Can this choose the best diagonal for my room?
No. Use this result with viewing distance, sight lines and projector throw rather than treating one diagonal as universal.