🧮 Calculators & Daily Life

TV & Screen Size Calculator

From a diagonal size in inches and an aspect ratio, get the screen's width and height (cm/inches) plus a recommended viewing distance. Reverse-calculate inches from width/height, with a cheat sheet of common TV and monitor sizes. Everything stays in your browser.

Examples (click to try)
Mode
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Width (cm)
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Height (cm)
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Diagonal (cm)
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Width (in)
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Height (in)
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Viewing distance (4K: ~1.5x height)
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Viewing distance (Full HD: ~3x height)

Viewing distances are general TV guidelines. The best distance varies with monitor use and personal preference.

How to use

In "Inches → dimensions" mode, pick a diagonal size and an aspect ratio to get the width, height (cm/inches) and diagonal in cm. The math: diagonal cm = inches × 2.54, width = diagonal × W/√(W²+H²), height = diagonal × H/√(W²+H²). The tool also shows rule-of-thumb viewing distances for 4K (about 1.5x the screen height) and Full HD (about 3x). In "Dimensions → inches" mode, enter the width and height in cm to reverse-calculate the diagonal in inches and the closest common aspect ratio. Handy when buying a TV or checking whether a screen fits your stand or wall.

Examples

  • 55-inch TV (16:9) → 121.8 cm wide × 68.5 cm tall (diagonal 139.7 cm). For 4K, about 1.0 m viewing distance
  • 27-inch monitor (16:9) → 59.8 cm × 33.6 cm
  • 121.7 cm × 68.5 cm → about 55.0 inches, aspect ratio about 16:9

TV & monitor size cheat sheet (16:9)

Diagonal (in)Width (cm)Height (cm)Diagonal (cm)
2453.129.961.0
2759.833.668.6
3270.839.881.3
4088.649.8101.6
4395.253.5109.2
50110.762.3127.0
55121.868.5139.7
65143.980.9165.1
75166.093.4190.5
85188.2105.8215.9

FAQ

Is my data sent to a server?
No. Everything runs in your browser; nothing is transmitted or stored externally.
How is a TV size like 55 inches measured?
The advertised size is the diagonal of the visible screen in inches (55 in is about 139.7 cm), not including the bezel. This tool uses the same screen-diagonal convention.
How is the viewing distance estimated?
A common rule of thumb recommends sitting at about 1.5x the screen height for 4K TVs and about 3x for Full HD TVs. It is a general TV guideline — the best distance varies with monitor use and personal preference.
Can I calculate ratios other than 16:9?
Yes. Presets include 16:10, 21:9 ultrawide and 32:9, and the custom option accepts any width/height ratio. The dimensions-to-inches mode also detects the closest common ratio automatically.