TV Size & Viewing Distance Calculator
Find the best seating distance for a TV size — or the TV size for your couch — using the SMPTE and THX viewing-angle guidelines.
Sit about
6.5–8.8 ft away
- Farthest (SMPTE, 30° of view)
- 8.8 ft (2.69 m)
- Immersive (THX, 40° of view)
- 6.5 ft (1.98 m)
- Screen width × height
- 56.7 × 31.9 in
These are field-of-view guidelines from cinema standards; personal comfort and eyesight decide the rest.
Show the work
Screen width
width = diagonal × w ÷ √(w to the power of 2 + h to the power of 2)
65 × 16 ÷ √(16 to the power of 2 + 9 to the power of 2) = 56.7 in
Distances for 40° and 30° of view
distance = width ÷ 2 ÷ tan(angle ÷ 2) ÷ 12
56.7 ÷ 2 ÷ tan 20° ÷ 12; 56.7 ÷ 2 ÷ tan 15° ÷ 12 = 6.5–8.8 ft away
How it works
Screen width = diagonal × 16 ÷ √(16² + 9²) for 16:9; distance = (width ÷ 2) ÷ tan(angle ÷ 2), with SMPTE EG-18's 30° (farthest) and THX's 40° (immersive)
Questions
- How does the TV size & viewing distance calculator work?
- Screen width = diagonal × 16 ÷ √(16² + 9²) for 16:9; distance = (width ÷ 2) ÷ tan(angle ÷ 2), with SMPTE EG-18's 30° (farthest) and THX's 40° (immersive).
- What do I need to enter?
- I know, Screen size (diagonal), Seating distance, Shape. Optional fields can be left blank.
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