Display size

For the number of pixels measured vertically and horizontally per screen, see Display resolution.

On two-dimensional display devices such as computer monitors and television sets, the display size (or viewable image size or VIS) is the actual amount of screen space that is available to display a picture, video or working space, without obstruction from the case or other aspects of the unit's design. The viewable image size (often measured in inches or millimeters) is sometimes called the physical image size, to distinguish it from the "logical image size" (display resolution, measured in pixels) of various computer display standards.

The size of an approximately rectangular display is usually given by monitor manufacturers as the distance between two opposite screen corners, that is, the diagonal of the rectangle. This method of measurement is inherited from the method used for the first generation of CRT television, when picture tubes with circular faces were in common use. Being circular, only their diameter was needed to describe their size. Since these circular tubes were used to display rectangular images, the diagonal measurement of the rectangle was equivalent to the diameter of the tube's face. This method continued even when cathode ray tubes were manufactured as rounded rectangles; it had the advantage of being a single number specifying the size, and was not confusing when the aspect ratio was universally 4:3.

A problematic practice was the use of the size of a monitor's imaging element, rather than the size of its viewable image, when describing its size in publicity and advertising materials. On CRT displays a substantial portion of the CRT's screen is concealed behind the case's bezel or shroud in order to hide areas outside the monitor's "safe area" due to overscan. These practices were seen as deceptive, and widespread consumer objection and lawsuits eventually forced most manufacturers to instead measure viewable size. On cathode ray tube monitors, VIS differs noticeably from the full tube size, which is generally about 25 mm (1 in) larger.

Liquid crystal displays use 100% of their surface to display, thus the VIS is the actual size presented to the viewer.

In the U.S., manufacturers and retailers are allowed to list the tube size, which is misleading and confusing to many customers, especially when comparing both CRT and LCD models together. In many other countries, this practice is prohibited by consumer-protection laws.

1 Measurements and units
- 1.1 Conversion equations
- 1.2 Conversion charts
2 See Also

Measurements and units

The main measurements for display devices are:

Width and height
Total area
The diagonal, usually measured in inches. The diagonal measurement of a display as the actual viewable area is also dependent on the aspect ratio of the display. For a display device of the same area, the diagonal achieves a larger value in a widescreen than compared to a more square screen. There is a risk of manufacturers making displays wider than what is actually most convenient in order to make the diagonal achieve a larger value.

Conversion equations

The width and height can be calculated from the diagonal as follows:

$height=\sqrt{\frac{D^2 \times H^2}{W^2%2BH^2}}$

$width=\frac{W}{H} \times height$

, where:

D is the diagonal
W and H are taken from the aspect ratio as W:H, or, alternatively, by the screen resolution given by rows of pixels (assuming square-shaped pixels).

Conversion charts

These are charts of some common sizes of LCDs with varying aspect ratios and their actual viewable area.

Width, height and viewable area from diagonal measurement and aspect ratio, rounded to centimetres
(in)	(cm)	w (cm)	h (cm)	A (cm²)	w (cm)	h (cm)	A (cm²)	w (cm)	h (cm)	A (cm²)	w (cm)	h (cm)	A (cm²)
Diagonal		5:4			4:3			8:5			16:9
7	18	14	11	154	14	11	152	15	9	142	15	9	135
10	25	20	16	315	20	15	310	22	13	290	22	12	264
11	28	22	17	381	22	17	375	24	15	351	24	14	334
14	36	28	22	617	28	21	607	30	19	568	31	17	527
15	38	30	24	708	30	23	697	32	20	652	33	19	620
17	43	34	27	910	35	26	895	37	23	838	38	21	797
19	48	38	30	1136	39	29	1118	41	26	1047	42	24	995
20	51	40	32	1259	41	30	1239	43	27	1160	44	25	1103
21	53	42	33	1388	43	32	1366	45	28	1279	46	26	1216
22	56	44	35	1523	45	34	1499	47	30	1403	49	27	1334
23	58	46	36	1665	47	35	1638	50	31	1534	51	29	1458
24	61	48	38	1813	49	37	1784	52	32	1670	53	30	1588
25	64	50	40	1967	51	38	1935	54	34	1812	55	31	1723
26	66	52	41	2127	53	40	2093	56	35	1960	58	32	1864
27	69	54	43	2294	55	41	2258	58	36	2114	60	34	2010
28	71	56	44	2467	57	43	2428	60	38	2273	62	35	2161
29	74	58	46	2647	59	44	2604	62	39	2439	64	36	2318
30	76	60	48	2832	61	46	2787	65	40	2610	66	37	2481
31	79	61	49	3024	63	47	2976	67	42	2787	69	39	2649
32	81	63	51	3223	65	49	3171	69	43	2969	71	40	2823
33	84	65	52	3427	67	50	3372	71	44	3158	73	41	3002
34	86	67	54	3638	69	52	3580	73	46	3352	75	42	3187
35	89	69	56	3855	71	53	3794	75	47	3552	77	44	3377
36	91	71	57	4079	73	55	4013	78	48	3758	80	45	3573
37	94	73	59	4308	75	56	4239	80	50	3970	82	46	3774
38	97	75	60	4544	77	58	4472	82	51	4187	84	47	3981
39	99	77	62	4787	79	59	4710	84	53	4410	86	49	4193
40	102	79	63	5035	81	61	4955	86	54	4639	89	50	4411
41	104	81	65	5290	83	62	5206	88	55	4874	91	51	4634
42	107	83	67	5552	85	64	5463	90	57	5115	93	52	4863
43	109	85	68	5819	87	66	5726	93	58	5361	95	54	5097
44	112	87	70	6093	89	67	5995	95	59	5614	97	55	5337
45	114	89	71	6373	91	69	6271	97	61	5872	100	56	5582
46	117	91	73	6659	93	70	6553	99	62	6136	102	57	5833
47	119	93	75	6952	96	72	6841	101	63	6405	104	59	6090
48	122	95	76	7251	98	73	7135	103	65	6681	106	60	6352
49	124	97	78	7556	100	75	7435	106	66	6962	108	61	6619
50	127	99	79	7868	102	76	7742	108	67	7249	111	62	6892

The aspect ratio of 5:3 is found on several smartphones, such as those having a screen resolution of 480x800 pixels:

(in)	(cm)	w (cm)	h (cm)	A (cm²)
Diagonal		5:3
3.5	8.9	4.6	7.6	35
3.7	9.4	4.8	8.1	39
4	10.2	5.2	8.7	46
4.3	10.9	5.6	9.4	53
5	12.7	6.5	10.9	71

Display size

Contents

Measurements and units

Conversion equations

Conversion charts

See Also