Most people mount a television too high. It happens because the wall gets measured instead of the room: someone finds the middle of the empty wall, and the TV ends up where a picture would go rather than where your eyes are.
The number worth remembering
Sitting down, your eye line lands about 42 inches off the floor. That is the height the middle of the screen wants to be. Everything else is arithmetic.
Take half the screen height — not the diagonal, the actual height of the panel — and subtract it from 42. That is where the bottom edge of the TV goes.
A 65-inch television is roughly 32 inches tall, so half of that is 16. Forty-two minus sixteen leaves 26 inches from the floor to the bottom of the screen. On most walls that looks lower than people expect, right up until they sit down and watch something.
Why cinemas are the wrong reference
In a cinema the screen is above you and the seats are raked back, which is why nobody complains about neck strain. At home the sofa is upright and four times closer. The same angle that works in a theatre puts your neck at ten degrees of permanent tilt.
The comfortable range is roughly 15 degrees of upward tilt at most. Past that you feel it after an hour, and you will blame the sofa.
Where the rule breaks
Over a fireplace. A mantel usually sits at 48 to 54 inches, and the screen has to start above it. You are already 20 inches higher than ideal before anything is fixed to the wall. A tilting bracket claws back part of the angle; a pull-down mount solves it properly by bringing the screen down to eye level when you watch and parking it up when you do not. That is a separate question with its own answer, and heat matters more than height there.
Bedrooms. Watching lying down inverts the problem — the screen wants to be higher, not lower, and often tilted down. Measure from where your head actually rests, not from standing height.
Kitchens and bars. Standing viewers need the screen at 55 to 65 inches to the centre. This is the one place where the high mount is correct.
Two things people forget
The soundbar. If it goes under the screen, it needs 4 to 6 inches of clearance, and that pushes the whole assembly up. Decide about sound before deciding about height.
The outlet. A recessed outlet has to end up behind the panel, hidden. Once the height is set, the outlet position follows from it — not the other way round.
Check it before you drill
Cut a rectangle of cardboard the size of your screen and tape it to the wall at the height you calculated. Sit down. Watch it for a minute the way you would watch a film.
It sounds silly and it takes five minutes, but it is the only test that accounts for your ceiling, your sofa and your window glare all at once. Every installer who has been doing this for a while has watched a customer change their mind at exactly this point — usually downward, by four to six inches.
We do this at the marking-out stage on every job. The measurement takes a minute; getting it wrong costs a set of holes in a wall you have to patch.