Screen Size Calculator (Width & Height from Diagonal)
Calculate a screen or TV's physical width and height from its diagonal size and aspect ratio.
About the Screen Size Calculator (Width & Height from Diagonal)
A screen's diagonal measurement alone doesn't tell you how much physical width or height it will occupy — that depends on its aspect ratio too. This calculator uses the Pythagorean theorem to split a diagonal measurement into its width and height components for any given ratio.
Formula: Scale Factor k = Diagonal ÷ √(Ratio Width² + Ratio Height²), then Width = k × Ratio Width and Height = k × Ratio Height
This is useful when shopping for a TV or monitor and you need to know whether it will physically fit an entertainment center or desk, or when comparing how much taller a 4:3 screen is than a 16:9 screen at the same diagonal size. Manufacturers favor advertising diagonal size because it produces a larger, more attractive-looking number than either width or height alone would.