Why a 50-inch screen is not 50 inches wide
The number on the box is the diagonal, corner to corner. The width follows from the shape: on a 16:9 panel the diagonal is 2.0397 times the height, so 50 inches of diagonal leaves 24.5131 inches of height and 43.5788 inches of width. Shown to two decimals that is 43.58 by 24.51 inches, or 110.69 by 62.26 cm, and the glass covers 1,068.2 square inches — 6,892 square centimetres.
Change the shape and the same diagonal spreads differently. A 50-inch 21:9 panel is 45.96 inches wide but only 19.70 inches tall: 2.38 inches wider, 4.82 inches shorter and 15.3% less glass. A 50-inch 4:3 panel lands on exactly 40 by 30 inches. Same number on the box, three different pieces of wall.
Why public numbers for the same screen scatter
The widest spread this size gets is a range of 44.5 to 47.8 inches — 3.3 inches from one end to the other. The panel is one width. A range that wide is not a tolerance and not a manufacturing difference: both ends sit above 43.58 in, by 0.92 in and by 4.22 in, so neither end is this panel at all.
Shortcut multipliers. On a 16:9 panel the width is 0.8716 of the diagonal and the height is 0.4903 of it. Round those to 0.88 and to one half and 50 inches becomes 44.00 by 25.00 in. The width shortcut is 0.42 in over the panel (0.97%) and the height shortcut is 0.49 in over it (1.99%).
Rounding in centimetres. 127 cm is exactly 50 in, but the width is 110.69 cm, so a figure written as 110 cm is 0.69 cm short and one written as 111 cm is 0.31 cm long. A single centimetre is 0.39 in, which is most of a decimal place at this size.
Including the frame. A figure that takes in the bezel is wider than the lit panel by however thick the frame is on that model.
A neighbouring size leaking in. The top of that 44.5–47.8 range is 47.8 in. The next size up, 55 inches, is 47.94 in wide at 16:9 — 0.14 in away. That is an inference from the arithmetic, not something this page can prove about where the number came from, but it is the usual way a range like that appears: a bigger panel's width gets folded into a smaller panel's answer. What is certain is that a range is not an answer. The panel has one width, and it is 43.58 in.
Width and height by size
These are the 16:9 figures for the sizes sold most often. Bezel and stand are not included, so a real set is a little wider than the number here.
| Diagonal | Width | Height | Area |
|---|---|---|---|
| 43 in | 37.48 in / 95.2 cm | 21.08 in / 53.5 cm | 790 sq in |
| 50 in | 43.58 in / 110.7 cm | 24.51 in / 62.3 cm | 1,068 sq in |
| 55 in | 47.94 in / 121.8 cm | 26.96 in / 68.5 cm | 1,293 sq in |
| 65 in | 56.65 in / 143.9 cm | 31.87 in / 80.9 cm | 1,805 sq in |
| 75 in | 65.37 in / 166.0 cm | 36.77 in / 93.4 cm | 2,404 sq in |
| 85 in | 74.08 in / 188.2 cm | 41.67 in / 105.8 cm | 3,087 sq in |
The two sizes above this one have their own pages: how wide is a 65 inch tv gives 56.65 by 31.87 inches, and how wide is a 75 inch tv gives 65.37 by 36.77 with the shortcut multipliers that produce the whole-number figures people quote. Where to put the seat is a different question, and that one is worked out here.
How the numbers are calculated
Everything comes from the diagonal and the ratio, so nothing is looked up:
height = diagonal ÷ √((a ÷ b)² + 1)
width = (a ÷ b) × height
area = width × height
centimetres = inches × 2.54
square centimetres = square inches × 6.4516
diagonal in pixels = √(pixels wide² + pixels high²)
PPI = diagonal in pixels ÷ diagonal in inches
The ratio a:b is the width over the height, so 16:9 means 16 units across for every 9 down. For 50 inches at 16:9 the divisor is √((16 ÷ 9)² + 1) = 2.039729, and 50 ÷ 2.039729 = 24.5131. The pixel rows only run when a resolution is chosen; they do not change the width, the height or the area.
What is rounded
Width and height are shown to 2 decimals in inches and 1 decimal in centimetres, area to the nearest square inch with a thousands separator, and the centimetre area to the nearest square centimetre. PPI is shown to 1 decimal. The arithmetic runs at full precision and only the display is rounded, so a difference that reads as 0.00 at the shown precision is still a real difference in the panel.
The whole-inch line under the results is a separate calculation, not a rounding of the displayed figures: it takes the exact width and height up to the next whole inch, which is what whole-number listings do, and reports how far above the panel that lands. On a 16:9 panel it also prints the two shortcut multipliers, 0.88 × diagonal and diagonal ÷ 2, so you can tell which figure a listing used.
What is measured
These are the active panel measurements: the lit rectangle you watch. Bezels, the frame around the glass, the stand and the depth of the chassis are all excluded, so a 50-inch set will measure wider than 43.58 inches once you include the frame. Wall space is the width figure, because the panel is mounted flat; add clearance for the mount if it tilts.
Questions this page answers
So how wide is a 50-inch TV really?
43.58 inches across the glass, or 110.7 cm, for a 16:9 panel. The 50 is the diagonal, not the width.
Why does one page say 44.5 to 47.8 inches?
Because it is a range, and both ends sit above the panel: 0.92 in and 4.22 in above. A range that wide is not a tolerance, it is at least two different numbers being combined. The panel has one width.
How tall is it?
24.51 inches, or 62.3 cm, at 16:9. The 21:9 version of the same diagonal is 45.96 in wide and 19.70 in tall.
Will it fit between two shelves?
Compare your gap with 43.58 inches, then add the frame on both sides and a little room to lift it onto the mount. Height matters for where the bracket goes rather than for the wall width.
How much area is that, and how much more is a 55?
1,068.2 square inches at 16:9, which is 6,892 square centimetres. A 55-inch panel covers 1,293 square inches, 21% more glass for 10% more diagonal.
Does 4K change any of these numbers?
No. Resolution changes only the pixel rows: 4,406 pixels on the diagonal, 88.1 PPI, 0.288 mm per pixel at 50 inches. Width, height and area stay exactly where they were.
Is the 50 measured across the glass or the whole set?
Across the glass, corner to corner, with the frame excluded. That is why a set sold as 50 inches measures wider than 43.58 inches once you put a tape on the outside.