TV Size Calculator
Enter a TV diagonal size and aspect ratio to calculate the actual screen width and height in inches and centimeters.
TV Size Calculator
Screen width and height from diagonal
Width = diagonal × aspect_width ÷ √(aspect_width² + aspect_height²). Height = diagonal × aspect_height ÷ √(aspect_width² + aspect_height²).
How TV Dimensions Are Calculated
TV size is advertised by diagonal, but width and height depend on aspect ratio:
Width = diagonal × aspect_width ÷ √(aspect_width² + aspect_height²) Height = diagonal × aspect_height ÷ √(aspect_width² + aspect_height²)
**Common aspect ratios**: - 16:9 — standard HD/4K TVs and monitors - 21:9 — ultrawide monitors and cinema TVs - 4:3 — older TVs and some monitors
1 inch = 2.54 cm exactly.
**Note**: The advertised diagonal is the screen size, not including the bezel/frame. Actual overall dimensions will be slightly larger.
- Width and height from Pythagorean theorem
- 16:9 / 21:9 / 4:3 aspect ratios
- Diagonal excludes bezel
- Inches and centimeters
Worked Example
Example: 55-inch TV, 16:9 aspect ratio.
- √(16² + 9²) = √(256 + 81) = √337 ≈ 18.36 - Width = 55 × 16 ÷ 18.36 ≈ 47.9 inches - Height = 55 × 9 ÷ 18.36 ≈ 27.0 inches - Centimeters: 121.7 cm × 68.6 cm
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Open calculator →Frequently Asked Questions
Does diagonal include the bezel?
No. The advertised diagonal is the screen only. The bezel/frame adds to the overall width and height — measure your space with a little extra room.
What's the best TV size for my room?
A common guideline: viewing distance (inches) ÷ 1.6 ≈ recommended diagonal for 4K. So 8 feet (96 inches) viewing distance ≈ 60-inch TV.
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