Screen size calculator from diagonal
Useful before buying a TV or monitor to check it fits the space you have.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter diagonal, diagonal unit and aspect ratio.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Width = diagonal × W ÷ √(W² + H²), height = diagonal × H ÷ √(W² + H²), where W:H is the aspect ratio.
Example
Inputs: Diagonal = 55, Diagonal unit = Inches, Aspect ratio = 16:9. Result: Dimensions: 121.76 × 68.49 cm; Width in inches: 47.94 in; Height in inches: 26.96 in.
Limits and caveats
- Covers the viewable area only, not the bezel or stand.
- Commercial 21:9 screens are often 64:27 or 43:18 in fact, a difference of a few millimetres.
Questions about this tool
How wide is a 55 inch TV?
At 16:9 the screen is about 121.8 cm wide and 68.5 cm tall, without the bezel.
Is the screen size the width?
No, the advertised number is the diagonal from corner to opposite corner.
Why does a 4:3 screen have more area than 16:9 at the same diagonal?
A shape closer to a square encloses more area for the same diagonal.