40-inch TV dimensions, viewing distance and mounting height

How big is a 40-inch TV?

TV sizes are measured across the diagonal of the picture. For a 16:9 screen the width is 0.872 times the diagonal and the height 0.490 times, so a 40-inch screen is 34.9 × 19.6 inches (89 cm × 50 cm), with 4.7 square feet of picture.

43″ 37.5 × 21.1 in (95 × 54 cm)40″ 34.9 × 19.6 in (89 × 50 cm)32″ 27.9 × 15.7 in (71 × 40 cm)

Two things make a real set bigger than its screen. The frame: on the 2 current 40-inch models we list, the slimmest add almost nothing to the 34.9-inch picture width and the widest about 0.4 inches on each side. The stand adds height and, more importantly, depth. Some manufacturers also sell sets as a size “class”, with a measured diagonal slightly under the nominal size; the dimensions they print for the whole set are what matter for fit.

A 40-inch TV suits bedrooms and small rooms where you sit about four to five and a half feet away. Further back it starts to look small: the picture fills about 27° of your view at six feet and about 21° at eight.

It sits in an odd spot in today’s ranges. Many 40-inch sets are Full HD (1080p), while in most makers’ 4K ranges 43 inches is the smallest size. If you want 4K and HDR in a small room, compare the 43-inch models, which are only about 2.6 inches wider.

At around three feet wide, it fits on most dressers and narrow media units, and almost any wall between windows or doors.

Real 40-inch TVs, measured by their makers

Dimensions from each manufacturer’s US specification page, in inches. “Stand width” is how far apart the feet are, or the width of a pedestal, as the maker prints it; your console needs to be at least that wide. Two figures mean the feet fit in two positions; “narrow” means a stand under 40% of the TV’s width. Weight is without the stand; VESA is the wall-mount hole pattern in millimeters.

Without stands, these sets vary by only 0.3 inches in width and are 2.9–3.3 in deep. On their stands the depth ranges from 6.2–7.2 in, which is what decides whether the TV fits on a shallow shelf.

How far to sit from a 40-inch TV

The useful measure is the viewing angle: how much of your view the picture fills. SMPTE’s reference viewing distance gives about 31–33°, and THX’s cinema guideline is 40°. For a 40-inch screen, that band runs from about 4 ft (40°) to 5 ft 5 in (30°), measured from your eyes to the screen.

Resolution sets a second, closer limit. ITU-R BT.1845 and BT.2022 design viewing distances so that each pixel spans about one arcminute, roughly the limit of normal vision: 1.6 picture heights for 4K and 3.2 for 1080p. For a 40-inch screen that is about 2 ft 7 in for 4K and 5 ft 3 in for 1080p, so at normal sofa distances a 4K 40-inch set shows no visible pixel structure, while a 1080p set can look slightly soft if you sit at the near end of the band.

TV size & viewing distance calculatorEnter your seating distance to see the angle each size gives. Open →

How high to mount a 40-inch TV

For a sofa, aim the center of the screen at seated eye height, about 42 inches from the floor (Samsung’s guidance for an average adult on a typical couch). For a 40-inch TV that puts the bottom edge of the picture about 32 inches from the floor and the top about 52 inches.

If the TV has to go higher, THX suggests keeping your line of sight within 15° of the screen center. The further back you sit, the higher it can go:

Over a fireplace, a 40-inch TV usually ends up with its center well above 60 inches, past 15° from typical seats, and manufacturers warn about heat. Our fireplace guide covers both.

TV mounting height calculatorYour sofa, your distance, your mantel: get the center and bottom-edge heights. Open →

Will a 40-inch TV fit your room?

• Wall: the screen is 34.9 inches wide; the set about 35.7. Leave some wall either side, especially next to windows or a door frame.
• Console: design guides suggest a console a few inches wider than the TV, roughly 37–41 inches for a 40-inch set. The hard minimum is the stand width: feet near the edges need almost the full width of the TV.
• Room depth: with the sofa against the back wall, your eyes end up about two feet in front of it. Sitting 4 ft to 5 ft 5 in from a wall-mounted screen needs a room about 7 ft to 8 ft 6 in deep, more if the TV stands on a console or there is a walkway behind the sofa (36 inches is the usual minimum, from NKBA’s planning guidelines).
• Suits: bedrooms, small dens and offices.

The quickest check is to see it: open a room at your size in Room Studio with a 40-inch TV already on the wall, then drag the sofa to where yours sits.

40 inches compared with other sizes

Side-by-side comparisons: 32 vs 40 inch.