How is screen size measured?

Screen size is measured diagonally from one corner to the opposite corner, in inches. A 55-inch TV means the diagonal measurement is 55 inches. The actual width and height depend on the aspect ratio.

What is the difference between 1080p and 4K?

1080p (Full HD) has 1920×1080 pixels (~2 million). 4K (Ultra HD) has 3840×2160 pixels (~8.3 million) — exactly 4 times as many pixels. On larger screens (50+ inches) or at closer viewing distances, 4K provides noticeably sharper images.

How far should I sit from my TV?

For 4K TVs, the ideal viewing distance is 1-1.5 times the screen diagonal. For a 55-inch TV, sit 4.5-7 feet (1.4-2.1 m) away. For 1080p, multiply the diagonal by 1.5-2.5. Sitting too far negates the benefit of higher resolution.

Screen Size Guide: Inches, Resolution, and Aspect Ratios

TV Size Dimensions (16:9 Aspect Ratio)

Diagonal (in)	Width (in)	Height (in)	Width (cm)	Height (cm)
32	27.9	15.7	70.8	39.9
43	37.5	21.1	95.2	53.6
50	43.6	24.5	110.7	62.3
55	47.9	27.0	121.7	68.5
65	56.7	31.9	143.9	80.9
75	65.4	36.8	166.1	93.5
85	74.1	41.7	188.2	105.9

Common Resolutions

Name	Pixels	Total Pixels	Aspect Ratio
HD (720p)	1280 × 720	921,600	16:9
Full HD (1080p)	1920 × 1080	2,073,600	16:9
QHD (1440p)	2560 × 1440	3,686,400	16:9
4K UHD	3840 × 2160	8,294,400	16:9
Ultrawide	3440 × 1440	4,953,600	21:9
8K	7680 × 4320	33,177,600	16:9

Phone Screen Sizes

Size Category	Diagonal	Width (mm)	Height (mm)
Compact	5.4-6.1"	64-71	131-147
Standard	6.1-6.4"	71-74	147-158
Large	6.5-6.9"	74-77	158-165

Optimal Viewing Distance

For 4K TVs, multiply screen diagonal by 1-1.5 for the ideal viewing distance in the same unit. A 65" TV is best viewed from 65-97 inches (5.4-8.1 feet) away.

Convert screen dimensions with our length converter.