Screen diagonal from width and height
If you do not know your screen size, measure the lit area and enter the two numbers.
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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 width, height and unit.
- 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
Diagonal = √(width² + height²) by Pythagoras, then converted to inches by dividing by 2.54 if measured in cm.
Example
Inputs: Width = 121.76, Height = 68.49, Unit = Centimetres. Result: Diagonal in inches: 55 in; Diagonal in cm: 139.7 cm; Width to height ratio: 1.778.
Limits and caveats
- Measure the lit area only, without the bezel, or the result will come out larger than the advertised size.
Questions about this tool
How do I find my screen size in inches?
Measure the lit width and height in cm and enter them to get the diagonal in inches.
Why is my result slightly off the label?
Makers round the diagonal, and a hand measurement adds a small error.
How many cm are in an inch?
One inch is exactly 2.54 cm.