TV size calculator
Enter the diagonal size in inches: get the screen's actual width and height (16:9 panel) in inches and centimeters, plus the recommended viewing distance for your couch.
Measurements refer to the 16:9 panel only, bezels excluded.
Common sizes compared
| Size | Width | Height | Recommended distance |
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What the inches on the box actually measure
The size printed on the box is the screen's diagonal, corner to corner: one inch is 2.54 cm, so a 55" TV has a diagonal of about 140 cm (4.6 ft). Width and height follow from the 16:9 aspect ratio via the Pythagorean theorem: the width is about 87% of the diagonal and the height about 49% — a 55" screen is roughly 48 inches wide and 27 inches tall. One detail people often miss: going up a size grows the area far more than it seems. A 65" TV has almost 40% more screen than a 55", even though it's "only" 10 inches bigger on paper.
How far away should you sit?
For 4K content, the rule of thumb is to sit at about 1.2–1.5 times the diagonal: for a 55" TV that's roughly 5.5–7 feet, close enough to enjoy the detail without seeing individual pixels. If you mostly watch Full HD or standard-definition channels, sit farther back — around 2 times the diagonal. Before buying, measure the distance from your couch to the wall: it's the quickest way to tell whether the next size up is worth it or would just be uncomfortable to watch.