Screen Resolution Calculator
A screen’s width, height and area from its diagonal and aspect ratio, a size comparison, and the resolution for a pixel density.
Your screen
Filled in with example values. Replace them with your own.
Optional
See how much bigger or smaller a second screen is by area.
Results update as you type.
Result
27" 16:9: 23.53 × 13.24 in, 311.5 sq in
Screen size
23.53 × 13.24 in
- Width
- 23.53 in · 59.77 cm
- Height
- 13.24 in · 33.62 cm
- Area
- 311.5 sq in · 2,010 cm²
How it’s calculated
Width
27 × 16 ÷ √(16² + 9²) = 23.53 in
Height
27 × 9 ÷ √(16² + 9²) = 13.24 in
Area
23.53 × 13.24 = 311.5 sq in
How the screen resolution calculator works
A screen’s diagonal and aspect ratio fix its shape and size. The calculator splits the diagonal into width and height with Pythagoras’ theorem, gives the area, and can compare it with a second screen.
In the second mode, it works out how many pixels across and down a screen of that size needs for a pixel density you choose.
The formula
Width = Diagonal × W ÷ √(W² + H²)
Height = Diagonal × H ÷ √(W² + H²)
Pixels across = Width × PPI
W:H is the aspect ratio, for example 16:9. 1 inch = 2.54 cm.
Worked examples
- A 27-inch 16:9 screen: √(16² + 9²) = 18.36, so it is 27 × 16 ÷ 18.36 = 23.53 by 13.24 inches, an area of 311.5 square inches.
- A 32-inch 16:9 screen has 40.5% more area than that 27-inch one.
- For 110 PPI on the 27-inch screen: 23.53 × 110 = 2589 and 13.24 × 110 = 1456, so about 2589 × 1456 pixels.
Frequently asked questions
Why is a 32-inch screen so much bigger than a 27-inch one?
Area grows with the square of the diagonal. A 32-inch 16:9 screen is (32 ÷ 27)² = 1.40 times the area of a 27-inch one, about 40% more, although the diagonal is only 19% longer.
Does a wider screen have more area at the same diagonal?
No, less. For the same diagonal, the closer a screen is to square, the more area it has. A 27-inch 21:9 screen has less area than a 27-inch 16:9 one.
What pixel density should I aim for?
It depends on how far away you sit and on your eyesight, so the calculator leaves it to you. The PPI Calculator shows the density of screens you already know, which is a good way to choose.
How is this different from the PPI Calculator?
The PPI Calculator starts from a resolution and finds the pixel density. This calculator starts from a size and a density and finds the resolution, or the physical size alone.