Screen Size Calculator
Calculate screen width, height, area, and diagonal from aspect ratio. Compare monitor, laptop, TV, and phone screen dimensions.
in
Width 23.53 in
Height 13.24 in
Area 311.57 sq in
in
in
Diagonal 27.00 in
Aspect Ratio 16:9
Area 311.57 sq in
Screen Size Formula
Diagonal = sqrt(width^2 + height^2)
From aspect ratio a:b and diagonal d:
Width = d x a / sqrt(a^2 + b^2)
Height = d x b / sqrt(a^2 + b^2)
Frequently Asked Questions
- Use the Pythagorean theorem: Diagonal = sqrt(width^2 + height^2). This gives the diagonal measurement, which is how screens are normally marketed.
- Use the diagonal together with the aspect ratio. A 16:9 screen with a known diagonal can be converted into exact width and height because the ratio fixes the screen proportions.
- Aspect ratio describes the proportion between width and height. Common ratios include 16:9, 16:10, 4:3, and 21:9.
- Yes. TVs, monitors, phones, tablets, and laptops are usually measured from one corner of the visible screen to the opposite corner, not by width alone.
- A 27-inch 16:9 monitor has a visible screen width of about 23.5 inches and a height of about 13.2 inches.
- Yes. The same geometry works for TVs, monitors, laptops, tablets, and projection screens as long as you know the aspect ratio.
- If aspect ratios differ, the width and height will differ even when the diagonal is the same. For example, an ultrawide 21:9 display is wider and shorter than a 16:9 display with the same diagonal.
- Multiply inches by 2.54 to get centimeters. A 27-inch screen diagonal is about 68.58 cm.