Diagonal TV Measurements in Two Aspect Ratios

Televisions have traditionally been measured by their diagonal size. I have no idea why, nor am I inclined to look it up. This wasn't really a problem when all TVs had a screen aspect ratio of 4:3 as consumers learned basically how big a TV would be by it's diagonal size. However with the introduction of widescreen 16:9 televisions, things have changed. The TVs are still measured diagonally, but since 4:3 is closer to square than 16:9 you get less total surface area for a 16:9 TV with the same diagonal measurement as a 4:3 TV. This isn't all that big of a deal, but considering the lack of 16:9 HD programming content, you'll still be viewing mostly 4:3 material on your brand new 16:9 TV; therefore you'll want to buy your new 16:9 widescreen television to have at least the same vertical height as your current 4:3 TV. The chart below compares the the diagonal measurements of both aspect ratios, based on similar vertical heights. For example, if you currently have a 27" 4:3 television, you can look and see that a 16:9 television would need to be around 33" to have a comparable screen height. Since I've never seen a 33" widescreen TV, you would probably round down to 32" or way up to 37", both of which are common sizes.

TV Comparison Chart (by Vertical Size)
4:3 Aspect Ratio		16:9 Aspect Ratio
Diagonal Size	Vertical Size	Vertical Size	Diagonal Size
13 in.	7.8 in.	7.84 in.	16 in.
14 in.	8.4 in.	8.33 in.	17 in.
15 in.	9 in.	8.82 in.	18 in.
16 in.	9.6 in.	9.31 in.	19 in.
16 in.	9.6 in.	9.81 in.	20 in.
17 in.	10.2 in.	10.30 in.	21 in.
18 in.	10.8 in.	10.79 in.	22 in.
19 in.	11.4 in.	11.28 in.	23 in.
20 in.	12 in.	11.77 in.	24 in.
20 in.	12 in.	12.26 in.	25 in.
21 in.	12.6 in.	12.75 in.	26 in.
22 in.	13.2 in.	13.24 in.	27 in.
23 in.	13.8 in.	13.73 in.	28 in.
24 in.	14.4 in.	14.22 in.	29 in.
25 in.	15 in.	14.71 in.	30 in.
25 in.	15 in.	15.20 in.	31 in.
26 in.	15.6 in.	15.69 in.	32 in.
27 in.	16.2 in.	16.18 in.	33 in.
28 in.	16.8 in.	16.67 in.	34 in.
29 in.	17.4 in.	17.16 in.	35 in.
29 in.	17.4 in.	17.65 in.	36 in.
30 in.	18 in.	18.14 in.	37 in.
31 in.	18.6 in.	18.63 in.	38 in.
32 in.	19.2 in.	19.12 in.	39 in.
33 in.	19.8 in.	19.61 in.	40 in.
34 in.	20.4 in.	20.10 in.	41 in.
34 in.	20.4 in.	20.59 in.	42 in.
35 in.	21 in.	21.08 in.	43 in.
36 in.	21.6 in.	21.57 in.	44 in.
37 in.	22.2 in.	22.06 in.	45 in.
38 in.	22.8 in.	22.55 in.	46 in.
38 in.	22.8 in.	23.04 in.	47 in.
39 in.	23.4 in.	23.53 in.	48 in.
40 in.	24 in.	24.02 in.	49 in.
41 in.	24.6 in.	24.51 in.	50 in.
42 in.	25.2 in.	25.00 in.	51 in.
42 in.	25.2 in.	25.49 in.	52 in.
43 in.	25.8 in.	25.98 in.	53 in.
44 in.	26.4 in.	26.47 in.	54 in.
45 in.	27 in.	26.96 in.	55 in.
46 in.	27.6 in.	27.45 in.	56 in.
47 in.	28.2 in.	27.94 in.	57 in.
47 in.	28.2 in.	28.44 in.	58 in.
48 in.	28.8 in.	28.93 in.	59 in.
49 in.	29.4 in.	29.42 in.	60 in.
50 in.	30 in.	29.91 in.	61 in.
51 in.	30.6 in.	30.40 in.	62 in.
51 in.	30.6 in.	30.89 in.	63 in.
52 in.	31.2 in.	31.38 in.	64 in.
53 in.	31.8 in.	31.87 in.	65 in.
54 in.	32.4 in.	32.36 in.	66 in.
55 in.	33 in.	32.85 in.	67 in.
56 in.	33.6 in.	33.34 in.	68 in.
56 in.	33.6 in.	33.83 in.	69 in.
57 in.	34.2 in.	34.32 in.	70 in.
58 in.	34.8 in.	34.81 in.	71 in.
59 in.	35.4 in.	35.30 in.	72 in.
60 in.	36 in.	35.79 in.	73 in.
60 in.	36 in.	36.28 in.	74 in.
61 in.	36.6 in.	36.77 in.	75 in.
62 in.	37.2 in.	37.26 in.	76 in.
63 in.	37.8 in.	37.75 in.	77 in.
64 in.	38.4 in.	38.24 in.	78 in.
65 in.	39 in.	38.73 in.	79 in.
65 in.	39 in.	39.22 in.	80 in.

4x3 (fullscreen) vs 16x9 (widescreen) image

In the image above both screens share the same diagonal size. The 16:9 screen, while slightly wider, is less than 90% the total area of the 4:3 screen, and has less than 82% the vertical height.

4x3 (fullscreen) vs 16x9 (widescreen) for 4:3 content image

What's worse is when viewing standard definition (4:3) content. On a 16:9 screen, 4:3 content will be less than 67% the size (in area) of the same content on a 4:3 screen with the same diagonal size.

4x3 (fullscreen) vs 16x9 (widescreen) with same vertical size image

In this image both screens share the same vertical size. The 16:9 screen is now much wider, has more area, and will display 4:3 content at the same size as the 4:3 screen.