Which TV size for which seating distance? The rules of thumb

"What size should it be?" is the first question in almost every consultation – and the answer is not in the brochure but in the living room: it follows from the distance between sofa and wall. Anyone who measures that distance and applies one of the following formulas buys the right diagonal.

The rule of thumb by resolution

The rule: seating distance = screen diagonal × factor. The factor depends on how finely the picture is resolved, because from too close you see individual pixels, from too far you waste detail.

Since almost all sets from 43 inches upwards are 4K today, the factor of 1.2 to 1.6 is the rule we work with. Take the smaller value for film nights, the larger one if the television mostly runs in the background.

Seating distance and recommended diagonal at 4K

Measure from the picture surface to the eyes, not to the edge of the sofa.

Viewing angle per THX and SMPTE

The film industry counts not in inches but in degrees: how much of the field of view does the picture fill? SMPTE recommends at least 30 degrees of horizontal viewing angle for cinemas; THX names 36 to 40 degrees as the target for the best row. Converted to a 16:9 picture, 30 degrees means a distance of about 1.6 times the diagonal, 40 degrees around 1.2 times – exactly the range from the rule of thumb. So anyone wanting a "cinema feeling" with 4K material sits towards the near end of the table.

Why most people buy too small

In the shop a 75-inch set hangs next to an 85-inch one in a hall ten metres wide; at home it stands alone on a four-metre wall. The scale shifts, and almost all customers we ask after installation say: "bigger would have been fine." Two tips from practice: tape the picture area on the wall with masking tape and look at it for two days. And think in width: 65 inches is 145 cm wide, 77 inches 171 cm, 85 inches 189 cm. If the width fits the furniture and the wall recess, the size fits.

A second reason is the price jump between two sizes. The decision "one class smaller, but the better panel" is sometimes right – when the distance really is short. At over three metres, area almost always wins.

When a projector makes more sense

Televisions exist today up to 98 and 100 inches, but they are heavy, deep and do not fit through every stairwell. From about 3.5 metres of seating distance and a wish for over 100 inches, a projector with a screen becomes the superior solution: 120 inches corresponds to 2.66 metres of picture width, and the picture disappears during the day when the screen is retracted. The precondition is that the room can be darkened – for living rooms flooded with light, a large television or a laser TV with a special screen remains the better choice.

Conclusion

Measure the distance, multiply by 1.2 to 1.6, choose the diagonal in that range – and in doubt the larger one. We measure the seating distance at your home and tape the diagonal on the wall before you commit; anyone who brings the wall width and the distance goes home with a clear figure.