Room planning tool
TV Viewing Distance Calculator
Enter your screen's diagonal size and this calculator estimates a recommended seating-distance range, from a closer, more cinematic distance to a farther, more comfortable one.
Find your viewing distance range
Enter your screen's diagonal size. You'll get a range: a closer distance for a more cinematic, enveloping picture, and a farther distance for a more comfortable, mixed-use one.
Where these numbers come from
This calculator uses two published viewing-angle guidelines, not one invented number, because the "right" distance depends on what you're optimizing for:
- SMPTE EG-18 (Society of Motion Picture and Television Engineers) recommends a minimum horizontal viewing angle of about 30 degrees for a comfortable, mixed-use room. That works out to distance ÷ 0.625 when solving for diagonal, or diagonal ÷ 0.625 when solving for distance.
- THX's cinema-style guidance targets a wider, more enveloping viewing angle of about 36 degrees for a recommended seat. That works out to diagonal ÷ 0.835 when solving for distance — a closer seat for the same screen size.
The calculator's near figure uses the THX ratio (closer, more immersive) and the far figure uses the SMPTE ratio (farther, more comfortable for mixed viewing, like watching TV as well as movies). Pick a spot in that range based on how you'll actually use the room — closer for a dedicated movie room, farther if the same seat also has to work for everyday TV and a wide field of view feels tiring.
Compare the result against your room's real furniture layout and sightlines before finalizing seating — see the full home theater setup guide for how this step fits into the rest of the planning order, and the home theater projector guide for how projector throw distance interacts with screen size.
Once you know your target distance, see good projectors for home theater for specific models worth buying at that throw distance.
Planning notes
- This assumes a roughly centered, head-on seat. An off-center seat sees a narrower effective angle than the number the calculator gives.
- A projector image's throw distance depends on the specific projector's throw-ratio range, not on viewing distance alone — check that separately before assuming a given room depth works.
- For a very large room where the SMPTE far distance still feels small relative to the space, distance is still the limiting factor for picture quality — a bigger screen, not a closer couch, is usually the better fix.
Viewing distance questions
Which distance should I actually pick — near or far?
Near (THX) if the room is a dedicated movie space and you want a more enveloping picture. Far (SMPTE) if the same seat also does regular TV-watching, where a very wide angle can feel tiring over longer, more relaxed viewing.
Does this apply to projectors as well as TVs?
Yes — the viewing-angle math is the same regardless of what's producing the image. For a projector, also confirm the specific model's throw-ratio range supports your room's actual depth.
Why do SMPTE and THX disagree?
They're optimizing for different things. SMPTE EG-18 sets a minimum for professional mastering and review environments; THX's guidance is built around a more immersive, cinema-style experience. Neither is "wrong" — they're different targets.