Viewing distance is the distance between where you typically sit and the television screen. It matters because the ideal screen size depends on it: a screen that looks perfectly sized from three metres away can feel overwhelming from one and a half metres, or too small if the distance is much greater.
For 4K televisions, a commonly used guideline is that the screen looks sharp and immersive at a distance of roughly 1.2 to 1.5 times the screen's diagonal measurement, noticeably closer than the older rule of about 2.5 times the diagonal that applied to lower resolution screens. At the closer distances 4K allows, individual pixels are not visible, so the extra resolution is fully used rather than wasted.
Measuring the actual distance from the main seating position to where the television will sit, then checking it against the screen sizes being considered, is the most reliable way to choose a size that neither strains the eyes up close nor looks small from across the room. See our guide to TV size and viewing distance for a detailed table.
