Screen Size Comparison

Screens are sold by their diagonal, but two screens with a similar diagonal can be very different in size. A 34-inch ultrawide is about as tall as a 27-inch 16:9 monitor, just much wider, while a 32-inch 16:9 screen is taller than both. This screen size calculator turns the diagonal and aspect ratio into the real width and height in inches and centimeters, works out the screen area and, if you enter the resolution, the pixel density. Both screens are drawn to scale so you can see the difference at a glance before you buy a monitor, TV or laptop.

A screen is a rectangle, so its diagonal, width and height form a right triangle. For an aspect ratio W:H, the width is diagonal × W ÷ √(W² + H²) and the height is diagonal × H ÷ √(W² + H²). For example, a 27-inch 16:9 screen is about 23.5 inches wide and 13.2 inches tall.

These are the dimensions of the visible picture. The outer size of the device is a little larger because of the bezel and stand.

Ultrawide monitors (21:9) and super ultrawides (32:9) have a large diagonal because they are wide, not because they are tall. When you compare them with 16:9 screens, look at the height row: if the heights match, the ultrawide simply adds space on the left and right. That is why a 34-inch 21:9 monitor is often compared with a 27-inch 16:9 one, and a 49-inch 32:9 screen with two 27-inch monitors side by side.

Pixel density tells you how sharp text and images look at the same viewing distance. It is the number of pixels along the diagonal divided by the diagonal in inches. A 27-inch 2560x1440 monitor has about 109 PPI, while the same size at 3840x2160 has about 163 PPI. Enter the resolution of each screen to compare them.