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Screen Size Calculator

Unit Converters

Diagonal inches to width/height cm, 16:9/4:3/21:9

Quick Answer

Screen Size Calculator: Diagonal inches to width/height cm, 16:9/4:3/21:9. Screen Size Calculator uses standard unit conversion formulas to compute accurate results instantly.

Screen parameters

inch
Width × height121.8 × 68.5 cm
Screen area0.834 m² · 8339 cm²
Diagonal55 in = 139.7 cm

How it works

  1. 1Diagonal factor = √(16² + 9²) = 18.3576
  2. 2Width = 55 × 16/18.3576 × 2.54 = 121.76 cm
  3. 3Height = 55 × 9/18.3576 × 2.54 = 68.49 cm

Calculated value is the screen glass size; the bezel and cabinet add roughly 1-3cm on each side — leave margin when measuring a TV cabinet or wall niche.

16:9 matches mainstream video with no letterboxing; 4:3 plays old footage; 21:9 suits cinematic content and desktop productivity.

Pick viewing distance by resolution: 4K ≈ 1.5-2× the diagonal; 1080P ≈ 2.5-3×. See the TV viewing-distance calculator.

Check the VESA hole pattern and wall load capacity before wall-mounting; 65in+ TVs need two people to install.

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How to Use

  1. Pick units: switch source and target units in the Screen Size Calculator.
  2. Enter a value: results sync both ways instantly — no convert button needed.
  3. Use the reference table: common conversions are listed for instant lookup.
  4. Copy the result: copy the converted value with its unit.

Key Points

  • Screen Size Calculator is a free online unit conversion tool — open and use, no sign-up.
  • All calculations run locally in your browser; your data never leaves the device.
  • Key capability: Diagonal inches to width/height cm, 16:9/4:3/21:9.
  • Results come with formulas and reference tables so you can verify every number.

Formula & How It Works

Screen Size Calculator formula

Screen Size Calculator uses standard unit conversion formulas to compute accurate results instantly.

FAQ

How do I use the Screen Size Calculator?
Open the page and fill in the input fields — results update automatically. Diagonal inches to width/height cm, 16:9/4:3/21:9.
Are the results accurate?
Yes. Standard formulas and conversion factors are used and verified.
Is it free? Do I need to sign up?
Completely free. No registration, login or download required.
Does it work on mobile?
Yes. The responsive design works on phones, tablets and desktops.
Is my data saved?
No. Everything runs locally in your browser.

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Source & Updates

Based on SI conversion factors and international standards. Last updated: 2025-07

Authoritative sources:

Last updated:

Formulas and content on this page are reviewed by the YiJianSuan team. For reference only — official sources prevail.

Maintained and periodically reviewed by the YiJianSuan editorial team — review process in ourEditorial Policy.

Cite this page: YiJianSuan. Screen Size Calculator[EB/OL]. https://www.yijiansuan.com/en/c/convert/screen-size

Results provided by this tool are for reference only and do not constitute professional advice.