TV Size Calculator
Enter your viewing distance to calculate the ideal TV size (inches and cm) for your room.
TV parameters
Resolution
Screen diagonal length
Viewing parameters
Optimal distance (THX 40°)
Minimal distance (pixels invisible)
How Is the Ideal TV Size Calculated Based on Viewing Distance?
The ideal TV size depends on viewing distance and the resolution of content you plan to watch. Two international standards provide the reference points for this calculation: THX and SMPTE.
Viewing Distance Standards
Screen covers 40° of horizontal field of view. Recommended for cinema-quality immersive viewing. Distance ≈ screen width × 1.37.
The full screen is visible with eyes fixed at the centre. Suitable for large rooms or multiple viewers. Distance ≈ screen width × 1.9.
Effect of 4K (UHD) vs 1080p (FHD) Resolution on Viewing Distance
Resolution determines the minimum distance at which individual pixels can be distinguished. 4K screens have four times the pixel density of 1080p, so the pixel structure disappears at a much closer distance. This means a much shorter minimum viewing distance for the same physical screen size.
| Screen | Min. 1080p | Min. 4K | 4K advantage |
|---|---|---|---|
| 43" | ~1,1 m | ~0,55 m | Noticeable up close |
| 55" | ~1,4 m | ~0,7 m | Noticeable under 2 m |
| 65" | ~1,6 m | ~0,8 m | Noticeable under 2.5 m |
| 75" | ~1,9 m | ~0,95 m | Noticeable under 3 m |
What Is the Difference Between Inches and Screen (cm) Dimensions?
In TVs the "size" value expresses the diagonal length in inches — a US-originating industry standard. The diagonal runs from the bottom-left to the top-right corner of the screen and does not include the bezel (frame).
For a 16:9 aspect ratio, calculate actual screen dimensions as: Width (cm) = diagonal (cm) × 0.872 and Height (cm) = diagonal (cm) × 0.490. For example a 55" (139.7 cm) TV: 139.7 × 0.872 ≈ 121.7 cm wide and 139.7 × 0.490 ≈ 68.5 cm tall.
When buying, note that the physical dimensions on the box (width × height × depth) include the bezel and will be 2–5 cm larger than the diagonal-based calculation.
Room Standards to Consider When Buying a TV
The TV's centre should be at eye level or 5–10 cm below. Mounting too high causes neck strain.
The recommended viewing distance should be at least 60% of the room's depth. A 3 m deep room ideally suits a 55" or 65" screen.
Bright windows create screen glare. Choose a matte panel or anti-reflective coating; lower brightness in dark rooms.
If seating groups watch from more than 30° to the side, prefer OLED or IPS panels — VA and TN panels show colour shift at wide angles.
Leave at least 5–10 cm of air circulation space behind a wall-mounted TV; overheating shortens panel life.
Popular TV Sizes – Quick Reference
| Size | W × H | THX dist. | SMPTE dist. | Min. (4K) |
|---|---|---|---|---|
| 43" | 95 × 54 cm | ~1,1 m | ~1,5 m | ~0,5 m |
| 50" | 111 × 62 cm | ~1,3 m | ~1,8 m | ~0,6 m |
| 55" | 122 × 68 cm | ~1,4 m | ~1,9 m | ~0,7 m |
| 65" | 144 × 81 cm | ~1,7 m | ~2,3 m | ~0,8 m |
| 75" | 166 × 93 cm | ~2,0 m | ~2,7 m | ~0,9 m |
| 85" | 188 × 106 cm | ~2,2 m | ~3,1 m | ~1,1 m |