TV Size and Viewing Distance Calculator
Enter your room's seating distance to find the right TV size, or enter your screen size to find how far away you should sit. The calculator applies THX and SMPTE industry standards and accounts for resolution so you know exactly when pixels become invisible. Switch between inches and centimetres - results update instantly.
How TV size and viewing distance are related
The connection between screen size and seating distance comes down to viewing angle - the horizontal angle from edge to edge of the screen as seen from your seat. A wider angle fills more of your peripheral vision, making the image feel more immersive. Two industry standards define the target ranges. THX, the cinema audio and video certification company, recommends a 40-degree horizontal field of view for a cinematic home theater experience. SMPTE, the Society of Motion Picture and Television Engineers, recommends at least 30 degrees for comfortable everyday television. Sitting closer than about 26 degrees (the THX minimum) tends to feel overwhelming and may strain your eyes over long sessions.
Why resolution changes the calculation
Resolution determines the closest you can sit before individual pixels become visible to the naked eye. The human eye can resolve approximately one arc-minute of angle, equivalent to 1/60 of a degree. Below the pixel-limit distance the screen looks perfectly sharp regardless of how close you are. Above it, you may be able to see the pixel grid on lower-resolution screens. A 4K screen has four times the pixel density of a 1080p screen at the same size, so you can sit roughly twice as close to a 4K TV before pixels appear. This is why a 4K upgrade can justify sitting closer and choosing a larger screen, while a 1080p TV in a small apartment may already be sharper than you can detect from your sofa.
Screen dimensions: what the diagonal does not tell you
TV manufacturers measure screen size diagonally from corner to corner, which can be misleading when comparing screens side by side. A 16:9 screen that is 55 inches diagonally is about 47.9 inches wide and 27 inches tall. Going from a 55" to a 65" diagonal adds about 5.6 inches of width, but sounds like a much bigger jump. The width matters most for viewing angle calculations, and knowing the physical width and height can help you plan whether a new TV will fit on your wall or unit and stay within comfortable sight lines from every seat in the room.
Mounting height and eye-level placement
The ideal mounting height places the centre of the screen at seated eye level, roughly 42-48 inches from the floor for a standard sofa. Mounting a TV too high - above a fireplace mantle is the most common mistake - forces the neck into a sustained upward tilt that becomes uncomfortable after 30-60 minutes. If wall-mounting above a fireplace is the only option, use a tilting or full-motion mount so you can angle the screen downward and keep the centre point closer to eye level. Viewing distance and mounting height work together: a screen that is too high will also appear smaller in your effective field of view, making the optimal size recommendation less accurate.
TV size to viewing distance guide (4K resolution)
| TV size (in) | THX ideal (ft) | SMPTE comfortable (ft) | Pixel-limit distance (ft) |
|---|---|---|---|
| 32 | 3.5 | 4.6 | 2.1 |
| 40 | 4.3 | 5.8 | 2.6 |
| 43 | 4.7 | 6.2 | 2.8 |
| 50 | 5.4 | 7.2 | 3.3 |
| 55 | 6.0 | 7.9 | 3.6 |
| 60 | 6.5 | 8.7 | 3.9 |
| 65 | 7.1 | 9.4 | 4.3 |
| 70 | 7.6 | 10.1 | 4.6 |
| 75 | 8.1 | 10.8 | 4.9 |
| 85 | 9.2 | 12.3 | 5.6 |
Recommended seating distances in feet for common TV sizes at 4K resolution, following THX and SMPTE standards.
Frequently asked questions
What is the best TV size for a 10-foot viewing distance?
At 10 feet (120 inches) the THX standard recommends approximately a 75" screen for a fully immersive feel, while SMPTE puts the comfortable target around 56". Most people find 65" to 75" a practical sweet spot at 10 feet, with 4K resolution ensuring the picture stays sharp at the closer end of that range.
Does TV resolution change how far away I should sit?
Yes. Resolution determines the minimum distance at which the screen looks perfectly sharp. A 4K TV looks sharp from roughly half the distance a 1080p TV does at the same screen size. That means with 4K you can sit closer and enjoy the same or larger screen without ever seeing individual pixels - which is one of the main practical benefits of upgrading from 1080p.
Why do THX and SMPTE give different recommendations?
The two standards have different goals. THX calibrates home theater equipment to recreate the cinema experience, so it targets the wider 40-degree angle that fills your peripheral vision and feels immersive. SMPTE is primarily an engineering and broadcast standard aimed at comfortable viewing for extended sessions, so its 30-degree target is less tiring for everyday TV watching. Neither is "correct" - it depends on whether you want the cinema feel or the relaxed living-room experience.
Is a bigger TV always better?
A bigger screen is better up to the point where your seating distance cannot keep the image within the comfortable viewing angle range. If you sit too close to a very large screen the image fills too much of your visual field, which can feel disorienting and cause eye fatigue. The right size is the one that fills roughly 30-40 degrees of your horizontal field of view from where you actually sit.
How do I measure my TV screen size?
TV sizes are always measured diagonally from the upper-left corner of the screen to the lower-right corner, not including the bezel or frame. Use a tape measure and measure only the screen panel itself. The number on the box is almost always the diagonal in inches, even in countries that otherwise use metric measurements.
What is a good TV size for a bedroom?
Bedroom setups typically have a viewing distance of 6-9 feet from the foot of the bed to the TV. At 6 feet the SMPTE standard points to about a 40" screen, and at 9 feet to about 57". Most bedroom viewers choose 43" to 55" as a practical range. At these sizes and distances 4K makes little visible difference - a good 1080p or HDR set often looks just as sharp from a bed.
Does viewing angle affect picture quality on the TV itself?
Yes, in a different way. The viewing angle discussed in this calculator is the horizontal field of view from your seating position - how much of your vision the screen fills. Separately, TV panels have an off-axis viewing angle that describes how much colour and contrast shift when you view the screen from the side rather than straight on. OLED and QLED panels generally have better off-axis performance than standard IPS or VA panels.