TV Size & Mounting Height Calculator
How big a TV fits your room, and how high should it go? Enter your seating distance and TV size to get the size range, the mounting height, the tilt, and a neck-angle check, with a side view drawn to scale.
How this TV size and mounting height calculator works
Screen shape: for a 16:9 TV, width = diagonal × 0.872 and height = diagonal × 0.490.
Size for a distance: the screen's width should fill a chosen angle of your view. The width that fills an angle θ at distance d is 2 × d × tan(θ ÷ 2). At 30° the diagonal works out to about 0.61 × distance, and at 40° about 0.84 × distance. Put the other way, sit about 1.2 to 1.6 times the diagonal away.
Mounting height: the screen center goes at your seated eye height (42 in by default). Above a fireplace, the TV bottom sits at the mantel height plus your gap. The viewing angle is the arctangent of how far the screen center sits above your eyes divided by the distance. We warn at 15° or more upward.
Where the numbers come from
- 30° and 40°: SMPTE recommends a viewing angle of at least about 30° and THX recommends about 40° for a cinematic view. See this summary at Sound & Vision, plus THX and SMPTE. These are guidelines, not rules. Plenty of people like a bigger or smaller picture.
- Eye level mounting: the center of the screen at seated eye level, about 42 in from the floor, is the common recommendation. See Mount-It's guide and their fireplace guide.
- The 15° neck warning: a rule of thumb widely repeated in installer guides, not a medical standard. Comfort differs from person to person.
Tips
- Mount into wall studs or use rated anchors, and check the weight limit on the mount.
- Plan the power and cable route before you mount, ideally inside the wall using code-approved, in-wall rated parts. Ask an electrician if unsure.
- Do not mount a TV above a working fireplace without checking heat and clearance guidance from the TV and fireplace makers.
Planning guidance only. Always follow the TV and mount manufacturers' instructions.
Estimates only — not engineering, legal or code advice. Check requirements with your local building department and a licensed professional before you build.
Common questions
What size TV should I buy for an 8-foot viewing distance?
At 8 ft (96 in), the 30° (SMPTE) guideline gives a 59 in TV and the 40° (THX) guideline gives an 80 in TV. Common sizes in that range are 65, 75 and 77 inches.
How far should I sit from a 65-inch TV?
Between about 6.5 and 8.8 feet. At 8.8 ft the screen fills 30° of your view, and at 6.5 ft it fills 40°. Most people sit toward the middle of that range.
How high should I mount my TV?
A common rule is to put the center of the screen at seated eye level, usually 40 to 45 inches from the floor on a typical sofa. This calculator defaults to 42 inches and lets you enter your own seated eye height.
Is it OK to mount a TV above a fireplace?
It can work, but the screen is usually high. With a 54 in mantel, 6 in of clearance above it and a 65 in TV, the screen center is about 76 in from the floor. From 8 ft away that is an upward look of about 19.5°, past the roughly 15° comfort limit, so the calculator warns you. A lower mantel, a pull-down mount or sitting farther back all help.
Does tilting the TV fix a high mount?
It helps the picture, because most TVs look best when you view them straight on, but it does not reduce how far you tilt your neck. Tilt down by about the same angle you look up. Tilting mounts commonly offer around 5–15°, so check the one you buy.
How wide and tall is a 65-inch TV?
A 16:9 TV that measures 65 in diagonally is about 56.7 in wide and 31.9 in tall, not counting the frame or stand.