TV Size Calculator
Find the perfect TV size, viewing distance, and mounting height in seconds — all to scale.
At 4K, a 80" TV looks pixel-perfect beyond ~5.2 ft.
How this is calculated
Size is set by viewing angle: diagonal = 2 × distance × tan(angle/2) ÷ 0.8716.
At the 36° balanced angle and 9 ft (108″): 2 × 108
× tan(18°) ÷ 0.8716 = 80.5″, snapped to 80″.
What size TV should you get?
The right TV size comes down to one thing: how far away you sit. Sit too close to a big screen and you can't take in the whole picture; sit too far from a small one and you lose the detail you paid for. The simple rule for a 4K TV: take your seating distance in inches and divide by about 1.4 to get the ideal screen size. Sitting 9 feet away (108 inches)? That points to roughly a 77-inch TV — though anywhere from 65″ to 85″ works depending on whether you want a relaxed or cinematic feel. Enter your numbers above and we'll do the math, then show it to scale.
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Six more calculators — every one instant, to-scale, and shareable.
How to use this TV size calculator
- 1. Choose whether you know your seating distance or your TV size.
- 2. Drag the slider or type your number.
- 3. Read your recommendation and see it drawn to scale with a person for reference.
- 4. Switch to 4K or 8K to see whether the resolution is worth it at that distance.
Everything updates instantly — there's no button to press.
The formula behind it
We base recommendations on how much of your vision the screen fills — its viewing angle. The two recognized standards are SMPTE's 30° (a relaxed minimum) and THX's 40° (cinematic immersion), with ~36° as the balanced sweet spot. As a simple multiplier of the diagonal: distance ≈ 1.2× the diagonal for immersive, up to 1.6× for relaxed.
TV size by viewing distance
| Seating distance | Immersive (40°) | Balanced (36°) | Relaxed (30°) |
|---|---|---|---|
| 5 ft | 50" | 45" | 37" |
| 6.5 ft | 65" | 58" | 48" |
| 8 ft | 80" | 72" | 59" |
| 9 ft | 90" | 81" | 66" |
| 10 ft | 100" | 89" | 74" |
| 12 ft | 120" | 107" | 89" |
Snap to the nearest size you can actually buy (43, 50, 55, 65, 75, 85″). Most people land on 65″ for a standard 8–10 ft living room.