Screen Size
Calculate screen dimensions from diagonal and aspect ratio
How to use Screen Size
- 1Enter the size of the corner of the screen (inches or centimetres).
- 2Enter the width ratio (16:9, 21:9, 4:3 etc.).
- 3Reads the width and height of the visible screen area.
Search for screen size by diagonal
width = diagonal / √ (1 + (H/W)2); high = width x (H/W)The size of the screen is indicated by a diagonal line, but the visual width depends on the width ratio.
65 inches 16:9 TV is approximately 56.7 inches wide; and 21:9 is wider and shorter.
The inch of the screen indicates the length of the diagonal line, 1 inch = 2.54 cm. Known diagonal and width heights can be calculated at 16:9,** width = diagonal x 0.8716, high = diagonal x 0.4903**. For example, 55 inches: width = 55 x 2.54 x 0.8716 ≈ 121.8 cm. Conversely, 4:3 screens are wide 0.8, high 0.6; 21:9 superwide screens are wide 0.9143, high 0.3917.
** View distance determines how much to buy**: THX suggests a horizontal view of 36-40 degrees, corresponding to "watch distance ≈ screen heights 1.5 to 2 times " , with a rough mouth of ** distance (m) ≈ cornerlines (inches) x 0.05 to 0.07** (55 inches for 2.75-3.85 m is conservative and many people actually prefer larger and more immersed). More practical judgement: The standard distance for the SMPT 30 degree perspective = a diagonal x 1.6, i.e. about 65 inches 2.6 m. ** It's common experience to buy big or small ** — It's just starting to feel big, it's getting used to it a week later.
| Screen (16:9) | Large x High | Suggested view distance | Apply scene |
|---|---|---|---|
| 32 inches | 70.9 × 39.9 cm | 1.2 – 1.6 m | Small bedroom, computer monitor |
| 43 inches | 95.2 × 53.5 cm | 1.6 – 2.2 m | Small living room. |
| 55 inches | 121.8 × 68.5 cm | 2.0 – 2.8 m | Mainstream living room |
| 65 inches | 143.9 × 80.9 cm | 2.4 – 3.3 m | Big living room. |
| 75 inches | 166.0 × 93.4 cm | 2.8 – 3.8 m | Large living room/video studio |
| 85 inches | 188.2 × 105.8 cm | 3.2 – 4.3 m | Audio studio |
| 100 inches | 221.4 × 124.5 cm | 3.7 – 5.0 m | Family cinema |
Common screen size and view distance advice
Frequently asked questions
Is the diagonal line border?
Excludes; is a visible panel of angular lines, but some of the commercial boundaries are blurred.
Why does 21:9 look different?
A rectangle with a diagonal but wider and shorter; suitable for a film, not for a document.
How do you turn centimeters in?
Centimeter divided by 2.54 to get in.
How long does it take for a TV to see a difference?
It depends on the distance and sight. The human eye at the limit of 1 metre is determined by approximately 0.3 mm (20/20 ang.). Simple: **4K to discern differences, the viewing distance for screen heights should be greater than approximately 0.35**, i.e. within distance of the height of screens x 2.8. 65 inches (high 81 cm) corresponds to approximately 2.3 m, so 65 inches within 2.3 metres can distinguish more clearly than 1080 p. ** If you sit far (over 3 metres) or if the screen is less than 50 inches, the quality of 4K is not significantly elevated**, then more attention should be paid to HDR, colour field and brightness.
What is the relationship between resolution, PPI, size?
PPI (number of pixels per inch) = √ (widen pixel 2 + high pixel 2) ÷ diagonal inches. It determines the level of detail:** the PPI of the same 1080p, 24 inch monitor is about 92, while 55 inch television is only 40**, so it takes 4K to reach the view of the cell phone. Apple's standard for retina screens is: normal use of PPI at a distance up to no pixel point in human eyes (cell phone about 300+PPI, Laptop about 220+, TV about 60-80). ** To judge whether the screen is good, to look at resolution and size at the same time, only resolution is meaningless. **