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TV Viewing Distance Calculator: Angles and Pixel Detail
Find distances for a chosen 16:9 TV diagonal using a historical SMPTE 30° reference and THX 36–40° guidance. Compare 1080p, 4K and 8K pixel estimates or reverse the calculation.
TV Viewing Distance Calculator: Angles and Pixel Detail: Starts with a chosen TV size and shows distances from the viewer's eyes to the screen for three horizontal viewing angles. Separately estimates the distance where one square pixel spans one arcminute for 1080p, 4K and 8K. Reverse mode finds a diagonal from distance. Comfort and eyesight vary, so the results are planning references. Runs 100% locally in your browser with zero server file uploads.
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- Home & family tools
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- Free · no sign-up
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One arcminute per pixel: distance estimate
These angles are viewing preferences, not medical limits. SMPTE EG-18 (Design of Effective Cine Theaters, 1994; withdrawn in 2003) describes about 30° horizontally. THX's public cinema guidance uses 36°; its home rule, diagonal ≈ distance × 0.835, corresponds to about 40° for 16:9. Choose a distance that feels comfortable.
W = D × 16 / √337. Distance = W / [2 tan(θ/2)]. Reverse diagonal = 2 × distance × tan(θ/2) × √337 / 16. Use the same length unit throughout.
Retina distance = (screen height / vertical pixels) / tan(π/10800). This assumes square pixels and one arcminute visual acuity. It is not a guarantee that resolution differences vanish beyond that distance; eyesight, contrast, content and scaling matter.
TV size from sofa distance · Physical screen comparison · Screen PPI calculator
Historical SMPTE reference
SMPTE EG 18-1994, Design of Effective Cine Theaters, describes roughly 30° of horizontal field of vision. It was withdrawn in 2003. Official SMPTE publication: https://pub.smpte.org/latest/eg18/eg0018-1994_withdrawn2003.pdf . This page uses that angle as a historical cinema reference.
THX public guidance
THX recommends 36° horizontally from the farthest cinema seat: https://www.thx.com/questions/thx-certified-screen-placement/ . Its home-TV rule multiplies viewing distance in inches by 0.835 to estimate diagonal: https://www.thx.com/questions/what-size-tv-should-i-buy-for-my-living-room/ . For 16:9 this is approximately a 40° horizontal angle.
Formulas
Width W = diagonal D × 16/√337. Viewing distance = W/[2 tan(θ/2)]. Reverse D = 2 × distance × tan(θ/2) × √337/16. Pixel distance = (screen height/vertical pixels)/tan(π/10800), using one arcminute. Resolution rows are 1080, 2160 and 4320; this assumes square pixels and a 16:9 image.
How to use it
- Enter the diagonal of your 16:9 screen in inches.
- Compare the angle-based distances and pixel-detail estimates.
- Switch to distance-to-size mode to compare recommended diagonals.
Privacy & limitations
All size and distance calculations run in your browser.
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Frequently asked questions
Is SMPTE 30° a current household safety rule?
No. EG-18, Design of Effective Cine Theaters, is a historical cinema guideline withdrawn in 2003. The 30° value here is a descriptive planning reference, not a medical or building-code limit.
Why show both 36° and 40°?
THX's public cinema placement guidance uses 36°. Its home-TV sizing rule is diagonal ≈ distance × 0.835, which implies about 40° for a 16:9 screen.
What does retina distance mean?
It uses one arcminute per pixel as a visual-acuity assumption. It does not guarantee identical perceived image quality beyond that distance: contrast, eyesight, content, compression and scaling matter.
Can I start with my sofa distance?
Yes, switch to reverse mode, or use TV Size Calculator, which starts from room distance.
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