40-inch screen dimensions
34.9 × 19.6 inches
88.6 × 49.8 cm · 886 × 498 mm · 16:9 · Television size
Why the diagonal is not enough
Screens are advertised by their diagonal, and a diagonal does not determine width until you also know the shape. The same 40-inch measurement produces a screen 6.5 inches wider at 32:9 than at 4:3. If you are measuring a space, the width is the number that matters.
| Aspect ratio | Width | Height | Screen area |
|---|---|---|---|
| 16:9 — the standard for televisions and most monitors | 34.9 in / 88.6 cm | 19.6 in / 49.8 cm | 684 in² |
| 16:10 — taller than widescreen, common on laptops and design monitors | 33.9 in / 86.2 cm | 21.2 in / 53.8 cm | 719 in² |
| 21:9 — the 34-inch class ultrawide, actually 43:18 | 36.9 in / 93.7 cm | 15.4 in / 39.2 cm | 570 in² |
| 4:3 — the pre-widescreen shape, still used by projectors and older panels | 32.0 in / 81.3 cm | 24.0 in / 61.0 cm | 768 in² |
| 32:9 — two 16:9 panels side by side in one screen | 38.5 in / 97.8 cm | 10.8 in / 27.5 cm | 417 in² |
How it compares by area
A diagonal is a length, so a step up sounds smaller than it is: moving from 38 inches to 40 adds 2.0 inches of diagonal and 11% more picture, and the next size up, 43 inches, is another 16% again.
| Size | Width | Screen area | vs 40-inch |
|---|---|---|---|
| 27 in | 23.5 in | 312 in² | -54% |
| 29 in | 25.3 in | 359 in² | -47% |
| 32 in | 27.9 in | 438 in² | -36% |
| 34 in | 29.6 in | 494 in² | -28% |
| 38 in | 33.1 in | 617 in² | -10% |
| 43 in | 37.5 in | 790 in² | +16% |
| 49 in | 42.7 in | 1026 in² | +50% |
| 50 in | 43.6 in | 1068 in² | +56% |
Pixel density at 40-inch
The same resolution is sharp on a small screen and coarse on a large one, because sharpness is pixels per inch and the inches are not in the resolution.
| Resolution | Density at 40-inch | |
|---|---|---|
| Full HD (1920×1080) | 55 PPI | Fine across a room, coarse up close |
| QHD (2560×1440) | 73 PPI | Fine across a room, coarse up close |
| 4K UHD (3840×2160) | 110 PPI | Comfortable at desk distance |
| 8K UHD (7680×4320) | 220 PPI | Very high — the interface will be scaled |
Frequently asked questions
How wide is a 40-inch screen?
A 40-inch 16:9 screen is 34.9 inches (88.6 cm) wide and 19.6 inches (49.8 cm) tall. The diagonal alone does not fix the width — a 40-inch 4:3 screen is 32.0 inches wide instead.
What are the dimensions of a 40-inch TV in cm?
88.6 × 49.8 cm for the screen itself at 16:9. The cabinet is larger — usually 1 to 3 cm on each side for a modern set, more if it has a bezel — so measure the product rather than the panel when checking whether it fits a space.
Is a 40-inch screen much bigger than a 38-inch one?
By area, 11% bigger. Screens are sold by diagonal, which understates every step: going up 2.0 inches of diagonal here adds 11% of picture.
What resolution should a 40-inch screen be?
Pixel density decides that: Full HD gives 55 PPI, QHD gives 73 PPI, 4K UHD gives 110 PPI, 8K UHD gives 220 PPI. Below about 80 PPI a screen looks coarse at desk distance but is fine across a room, which is why televisions and monitors of the same size are sold at different resolutions.