40 inch TV dimensions

The 40 inch is the size people turn to when a 32 feels too small and a 50 will not fit, so the numbers that matter are the ones that decide where it goes: how much shelf, how much wall and how far back the seat is.

Which width do you mean?

• 88.6 cm is the picture alone, the part that lights up, worked out from the 101.6 cm diagonal and the 16:9 shape. It is the figure to compare sizes by.
• About 89.8 cm is the set including its bezels, and the width a shelf, an alcove or a gap between cupboards must beat.
• About 58.3 cm is how far apart the feet stand, which sets the narrowest stand that will carry it.

A set sold as a 40 inch can measure a little under 40 inches on the diagonal, because some makers name panels by size class. If a spec sheet differs from this page by a centimetre or so, believe the spec sheet.

40 inch TV size in cm, inches and feet

With the stand and without it

Standing on its feet, a 40 inch TV is about 56.6 cm tall: 51.6 cm of set on about 5 cm of foot. That is 22.3 in, low enough for a bedside chest or a kitchen worktop.

The feet matter more than the body for a small stand. At about 58.3 cm apart they let the set stand on a shelf much narrower than the set itself, with the ends of the screen hanging over, and they ask for a shelf about 25 cm deep. Wall mounted, the feet disappear and the bracket adds its own depth behind the set. That depth varies by model, so check it before you plan a shelf or a radiator below.

Drawn to scale

200 cm88.6 cm55.1 cm55.1 cm

Beside a standing adult a 40 inch is small. The picture is 49.8 cm tall, under a third of the figure’s height, and 88.6 cm across. That is a screen to look at from a chair or a bed, not one to fill a wall.

Next to the sizes either side

200 cm88.6 cm55.1 cm55.1 cm

The 32 inch is 20% narrower than the 40, with 36% less picture. The 42 inch is 5% wider with 10% more picture, and it is mostly sold as an OLED, so the choice between the two usually comes down to the panel type and not the five centimetres.

The step many people actually take is to the 43 inch, which adds about 7 cm of width and about 16% more picture for very little extra space. The one that changes a room is the 50 inch.

40 inch against 50 inch

Compare any two screens

In a 50 inch the picture grows 22.1 cm wider and 12.5 cm taller: 25% more on the diagonal and 56.3% more picture, so ten inches adds more than half again to what you are looking at.

Will it fit?

On a 120 cm wide unit the set uses 75% of the top and leaves 15.1 cm clear on each side. A 140 cm × 90 cm alcove beside a chimney breast gives about 25.1 cm on each side, which looks planned and not squeezed. The same set takes up only 45% of the width of a 200 cm × 120 cm wall, so on an open wall it can look lost.

A set this small is easy to carry in, so the bigger risk is the shelf: measure its depth against the 25 cm the feet ask for.

How far to sit

Comfortable viewing distance for a 40 inch television, by what it is used for

Used for	Sit	In feet	Field of view
General TV	1.4 m – 1.8 m	4 ft 9 in – 5 ft 10 in	28–34°
Sports	1.4 m – 1.7 m	4 ft 6 in – 5 ft 5 in	30–36°
Gaming	1.3 m – 1.7 m	4 ft 3 in – 5 ft 5 in	30–38°
Movies	1.2 m – 1.4 m	4 ft 0 in – 4 ft 9 in	34–40°
Home cinema	1.1 m – 1.4 m	3 ft 6 in – 4 ft 6 in	36–45°

Sit 1.4 m to 1.8 m away for everyday viewing and 1.2 m to 1.4 m for films. Those are the distances at which a 40 inch fills 28° to 34° and 34° to 40° of your view. The figure usually quoted from SMPTE is a 30 degree view and the one usually quoted from THX is 40, and the two bands straddle both.

That makes it a sofa in a small sitting room, a bed with the set on the opposite wall or a chair in a study. From 2.4 m, a common living-room distance, the picture spans about 21° of your view, short of the range above, and that is the point where a 50 inch or bigger starts to make sense. The viewing distance chart lists the range for every size.

Is 4K worth it on a 40 inch?

At 55 pixels per inch, a Full HD picture of this size stops showing single pixels from about 1.6 m by the usual 20/20 convention of 60 pixels per degree. A 4K one, at 110 pixels per inch, does so from about 0.8 m. The seat for a set this size is usually 1.4 m to 1.8 m away, which is right around that limit for Full HD and well beyond it for 4K. In practice, at a 40 inch, a 4K panel gives finer text and cleaner edges up close; it does not change what you see from the bed.

Treat “invisible from” as a rough guide. A 2025 paper in Nature Communications found a mean of about 94 pixels per degree for fine black and white detail, so people with sharp eyes can pick out slightly more than the convention allows. Buy a 40 inch on the panel and the picture processing before you buy it on the pixel count.

Fixing it to the wall

Wall brackets fit the pattern of threaded holes on the back of the set, which follows the VESA mounting standard and is quoted in millimetres. A 40 inch is among the lighter sets on sale, but the pattern still varies by model and the bracket has its own weight rating, so read both from the manual and not from the size. The bolts go into studs or masonry, never plasterboard alone. How high to put it is a separate question, and the guide to mounting height answers it.

Who a 40 inch suits

A 40 inch suits a room where the seat is close: a bedroom, a study, a kitchen, a caravan or the spare room that gets a film now and then. From 1.4 m to 1.8 m it fills a comfortable share of the view, and at 89.8 cm across it clears a 140 cm × 90 cm alcove and sits on a 120 cm wide unit without trouble.

It is the wrong size for a living room with the sofa three metres back, where it looks small, and for anyone who wants a big picture on a big wall. The TV size guide for a bedroom works through the bed-to-wall case with the same arithmetic, and the 32 inch page covers the next size down.