Why compare area, not inches
Screens are sold by the diagonal, but what you see is the area — and area grows with the square of the diagonal. Moving from a 55" to a 65" TV sounds like 18% more; it is 40% more picture. Shape matters too: a 34" 21:9 ultrawide is about as tall as a 27" 16:9 monitor but much wider, and a 16:10 laptop gives you more height than a 16:9 one with the same diagonal.
Viewing distance rule of thumb
For TVs, many people find 1.2–1.6× the screen diagonal a comfortable distance for 4K content: about 1.7–2.2 m (5.5–7 ft) for a 55" set. Use the drawing to check the TV will physically fit the wall or stand before you buy.
Questions
Why isn't a 65-inch TV 'twice' a 46-inch TV?
Screen size is the diagonal. Area grows with the square of the diagonal, so a 65" screen has about twice the area of a 46" screen of the same shape, even though the number is only 41% bigger.
Is a 34-inch ultrawide bigger than a 27-inch monitor?
It is wider, but similar in height to a 27" 16:9 monitor. Add both to see the overlap and the exact width, height and area difference.
How is width and height calculated?
From the diagonal and the aspect ratio: width = diagonal × W ÷ √(W² + H²), height = diagonal × H ÷ √(W² + H²). Bezels and curved screens are not included.
Can I compare my exact model?
Yes. Enter its diagonal and choose the aspect ratio in 'Add your own'. The ratio is printed in the spec sheet, or you can get it from the resolution (2560×1440 is 16:9).
Is it free?
Yes, no account needed. The site is supported by ads.