How to use the tv size and viewing distance calculator
- Choose whether you want the viewing distance for a TV you know, or the TV size for a seat you already have.
- Enter the screen size in inches, or the distance from your seat to the screen in feet.
- Pick the aspect ratio. Almost every modern TV is 16:9, and ultrawide screens are 21:9.
- Read the range between the 40 degree and 30 degree guidelines. Open the advanced option to add your own comfort angle.
Formula
Screen width = diagonal x ratio width / sqrt(ratio width^2 + ratio height^2)
Viewing distance = screen width / (2 x tan(angle / 2))
Screen diagonal = 2 x distance x tan(angle / 2) x sqrt(w^2 + h^2) / w
Common guideline angles: 30 degrees and 40 degrees
The angle is how much of your horizontal field of view the screen fills. About 30 degrees is a common minimum for a cinematic feel, and about 40 degrees is a commonly quoted limit for the most immersive seat. These are guidelines, not rules.
Worked example
A 65 inch 16:9 TV is 56.7 inches wide and 31.9 inches tall. For a 40 degree view the seat is 56.65 / (2 x tan 20) = 77.8 inches away, or 6 ft 6 in.
For a 30 degree view the seat is 105.7 inches away, or 8 ft 10 in. Anywhere between 6.5 and 8.8 feet suits the screen.
Going the other way, a couch 9 feet (108 inches) from the wall suits screens from 66 inches (30 degrees) up to 90 inches (40 degrees) on the diagonal.
Why distance matters more than size
A big screen far away and a small screen close up can look the same size to your eyes. What counts is how much of your vision the picture fills. Sit too far back and detail and impact are wasted. Sit too close and you may find yourself moving your head to follow the action.
A sharper screen lets you sit nearer without seeing pixels, which is why 4K sets are often placed closer than older HD sets of the same size. The calculator does not assume a resolution, so use your own judgment on whether you can see the pixel structure.
Beyond the numbers
Check these before you buy, because a calculator cannot see your room.
- Measure the wall or stand. The screen is wider than its diagonal suggests, and a 75 inch 16:9 TV is about 65 inches wide.
- Think about glare from windows and lamps, and where the light falls at the hours you watch.
- Consider a mix of uses. A seat that is perfect for movies may be too far for gaming or too close for a family sitting side by side.
- Leave space around the set for ventilation and cables.
Assumptions and limits
- The result is based on horizontal viewing angle only. Vertical angle and the height of the screen above the floor are not modeled.
- The 30 and 40 degree values are widely quoted guidelines. Personal comfort, eyesight and content change what feels right.
- Screen width uses the exact diagonal and ratio. Bezels and stands are not included.
- Distances are measured from the eyes to the screen surface and sizes are the marketed diagonal.
Frequently asked questions
How far should I sit from a 65 inch TV?
For a 16:9 set, about 6.5 to 8.8 feet puts the screen between 40 and 30 degrees of your view. Closer than that fills more of your vision, and farther away makes the screen feel smaller than it is.
What size TV do I need for a 10 foot viewing distance?
At 10 feet a 16:9 screen from about 74 to 100 inches fills between 30 and 40 degrees. Many people choose a smaller set for comfort and budget, and the range is a guide to the upper end.
Does the aspect ratio change the answer?
Yes. For the same diagonal a 21:9 screen is wider and shorter than a 16:9 one, so the viewing distance for the same angle is greater. Pick the right ratio in the form and the numbers update.
Is bigger always better?
Not always. A screen that is too large for the room makes you scan across the picture, and a very close seat can show compression and noise in the image. Choose a size you can see comfortably without turning your head.