How big is an 85-inch TV? Wall width, seat distance and room size

A TV's diagonal is measured across the picture, and at 85 inches that picture is 188.2 cm across and 105.8 cm tall. Most of the planning is about the room. Measure the wall, then the depth from the wall to the seat. The 40 degree seat is 2.6 m (8.5 ft)8.5 ft (2.6 m) away and the 30 degree seat is 3.5 m (11.5 ft)11.5 ft (3.5 m). A seat at least 2.6 m (8.5 ft)8.5 ft (2.6 m) back keeps the picture inside a 40 degree view.

From the 40 degree seat, the 4K pixels already blend together, because single pixels blur past 1.7 m (5.5 ft)5.5 ft (1.7 m).

Choose 85 inches for a large room with a wall at least 188.2 cm (74.1 inches)74.1 inches (188.2 cm) wide and a seat set at least 2.6 m (8.5 ft)8.5 ft (2.6 m) back. The panel measures 188.2 cm (74.08 in)74.08 in (188.2 cm) by 105.8 cm (41.67 in)41.67 in (105.8 cm), about 19,918 cm² (3087 in²)3087 in² (19,918 cm²) of picture.

Against a 77-inch, that's 22% more picture, and the wall needs 7 inches more width. Before the box arrives, measure the doorway and the route to the wall, since a set this size is a big box to carry.