Calculate the ideal seating distance based on your TV size and resolution.
1080p (HD)
4K (Ultra HD)
8K (Extreme HD)
Recommended Distances:
THX Ideal (40° View Angle):–
SMPTE Recommended (30° View Angle):–
Visual Acuity Distance (Pixel limit):–
* Distances are provided in feet. For 4K displays, sitting closer allows you to see more detail without seeing pixels.
How Viewing Distance Impacts Your Cinema Experience
Choosing the right seating distance is the difference between an immersive cinematic experience and a blurry, pixelated mess. If you sit too far away, you lose the benefits of high-resolution 4K or 8K displays. If you sit too close, your eyes may struggle to take in the whole screen, leading to eye strain.
THX vs. SMPTE Standards
There are two primary industry standards used to determine the perfect "field of view":
THX Standard: Recommends a 40-degree viewing angle. This is designed for maximum immersion, mimicking the experience of sitting in the "sweet spot" of a commercial movie theater.
SMPTE Standard: The Society of Motion Picture and Television Engineers suggests a minimum 30-degree viewing angle. This is generally preferred for mixed-use rooms where you might watch news or sports alongside movies.
The Role of Resolution
Resolution dictates the "Visual Acuity Distance." This is the point where the human eye can no longer distinguish individual pixels. For a 65-inch 1080p TV, you need to sit further back (about 8 feet) to avoid seeing the pixel grid. With a 65-inch 4K TV, you can sit as close as 4 feet and still see a perfectly smooth image.
Real-World Examples
Screen Size
Resolution
Ideal Range (Approx)
55 Inches
4K UHD
3.5 – 5.5 feet
65 Inches
4K UHD
4.0 – 6.5 feet
75 Inches
4K UHD
4.7 – 7.5 feet
85 Inches
4K UHD
5.3 – 8.5 feet
function calculateViewingDistance() {
// Get input values
var diagonal = parseFloat(document.getElementById('screenSize').value);
var resolution = parseInt(document.getElementById('resolution').value);
var resultArea = document.getElementById('resultArea');
// Validate input
if (isNaN(diagonal) || diagonal <= 0) {
alert("Please enter a valid screen size.");
return;
}
// 1. Calculate Screen Width (16:9 aspect ratio)
// Width = Diagonal * 0.87157
var screenWidthInches = diagonal * 0.87157;
// 2. THX Calculation (40 degree field of view)
// Formula: Distance = Width / 0.72
var thxDistanceInches = screenWidthInches / 0.72;
var thxDistanceFeet = thxDistanceInches / 12;
// 3. SMPTE Calculation (30 degree field of view)
// Formula: Distance = Width / 0.535
var smpteDistanceInches = screenWidthInches / 0.535;
var smpteDistanceFeet = smpteDistanceInches / 12;
// 4. Visual Acuity Distance (Based on resolution)
// High level simplified formula for visual acuity:
// 1080p: ~1.5 to 2.5x screen diagonal
// 4K: ~1 to 1.5x screen diagonal
// 8K: ~0.5 to 1x screen diagonal
var acuityFeet = 0;
if (resolution === 1080) {
acuityFeet = (diagonal * 1.5) / 12;
} else if (resolution === 2160) {
acuityFeet = (diagonal * 1.0) / 12;
} else {
acuityFeet = (diagonal * 0.5) / 12;
}
// Update the UI
document.getElementById('thxResult').innerHTML = thxDistanceFeet.toFixed(1) + " ft";
document.getElementById('smpteResult').innerHTML = smpteDistanceFeet.toFixed(1) + " ft";
document.getElementById('acuityResult').innerHTML = acuityFeet.toFixed(1) + " ft";
// Show the result box
resultArea.style.display = "block";
}