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TV size calculator
Enter your viewing distance and wall width. Get a sweet-spot diagonal based on SMPTE/THX viewing-angle guidelines — plus mount height and console width recommendations.
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Paste this on any home-electronics or AV blog. The calculator runs in an iframe with a link back.
<iframe src="https://plopit.app/tools/tv-size-calculator?embed=1" width="100%" height="800" frameborder="0" title="TV size calculator by PlopIt"></iframe>How the calculator decides
TV size is a function of viewing distance and resolution. SMPTE recommends the screen fill 30° of your field of view; THX pushes to 36-40°. For 4K content, those angles translate to a screen diagonal of roughly 1.2× (cinematic) to 1.5× (comfortable) the viewing distance in inches.
Resolution shifts the band. 8K allows sitting closer — pixels stay invisible at higher densities — so the divisor can drop to ~1.0×. 1080p forces sitting farther because pixels become visible; the divisor climbs to ~1.6-2.0×.
The wall caps the upper bound. Beyond about 75% of wall width, the TV looks pasted on rather than placed. The calculator clamps the recommendation at the smaller of the viewing-distance ideal and the wall-width maximum.
Standard sizes at a glance
| Diagonal | Width × Height | Ideal viewing distance (4K) |
|---|---|---|
| 43" | 37 × 21" | 5-6 ft |
| 55" | 48 × 27" | 6.5-8 ft |
| 65" | 57 × 32" | 8-10 ft |
| 75" | 65 × 37" | 9-11 ft |
| 85" | 74 × 42" | 10-13 ft |
Frequently asked questions
What size TV do I need for a 10-foot viewing distance?
For 4K content at 10 feet (120 inches) of seating distance, the sweet spot is a 65-75 inch screen. Cinematic preference pushes toward 80-inch; comfortable mixed-use settles around 65-inch. The rule: screen diagonal between 1.2x and 1.5x the viewing distance, depending on whether you lean immersive or comfortable.
How is TV size measured?
TV size is the screen diagonal in inches, corner to corner. A 65-inch TV in standard 16:9 aspect ratio is roughly 57 inches wide and 32 inches tall. Wall-mounted with no console, plan for an additional 1-2 inches around the panel for the bezel and mounting bracket.
What is the SMPTE rule for TV size?
SMPTE recommends the screen fill 30 degrees of horizontal field of view from the viewing position; THX recommends 36-40 degrees. In practice this maps to a TV diagonal of about 1.2x to 1.5x the viewing distance for 4K. Higher resolution (8K) allows sitting closer to the screen; 1080p forces sitting farther.
Can a TV be too big for a room?
Yes, in two ways. Physically, the TV should not occupy more than 75% of the wall width — beyond that it looks pasted on. Visually, sitting too close to a too-large screen produces eye strain over long sessions. The calculator caps the recommendation at both constraints.
How high should I mount a TV on the wall?
Center of the screen at seated eye level — roughly 42 inches from the floor for an average sofa-seated viewer. Mounting higher forces an uncomfortable upward viewing angle. Above-fireplace mounting is the most regretted decision in this category; use a tilting mount if it is the only option.
Does the calculator account for gaming distance?
Yes. Gaming benefits from sitting slightly closer because reaction time matters and screen content is more dynamic. The calculator shifts the recommendation toward the comfortable end of the band when 'Gaming' is selected, with a small safety margin.