# Determining Pixels Per Inch

"Pixels per inch" refers to the number of pixels that are packed into each inch of a computer monitor's display. The higher the number of pixels, the better resolution on the screen.

Determining Pixels Per Inch The Hard Way
To figure out the pixels per inch, consider the dimensions of the monitor and its resolution. First, keep in mind that the size of a monitor is often described in terms of the diagonal, and the screen resolution is described in terms of length and width. You need to bring the two together using the classic Pythagorean theorem. (Before your head explodes, what this means is that the diagonal of a right triangle squared equals the length squared plus the width squared. Feel free to use a calculator.)

So, what you need to do is calculate the screen resolution in terms of the diagonal. For example, let's say the native resolution of a computer screen is 1440 by 900. Square both of these, which will net you some large numbers (2073600 and 810000). Add those numbers together to get 2883600, and take the square root of that (or hit the square root button on your calculator). You'll get 1698, after rounding, which gives you the diagonal resolution of the screen.

Once you've gone through that, simply divide 1698 by the diagonal measurement of your screen in inches. If the diagonal measurement of your computer screen is 20 inches, then you have about 85 pixels per inch.

Determining Pixels Per Inch The Easy Way
For an even faster calculation, bust out a ruler and measure the width of your screen. Then divide the horizontal resolution, which is first number listed in a screen resolution, by the width. If the screen's horizontal resolution is 1024 and your monitor screen is 15.2 inches wide, then the pixels per inch should be about 67 pixels per inch.

Why Pixels Per Inch Matters
Getting a computer monitor with a high number of pixels per inch can be costly. You're better off finding a decent LCD monitor with evenly distributed backlighting so you don't get dark spots on the screen.

You can also adjust the computer's screen resolution to increase the illusion of more pixels per inch-however, you can't actually increase the number of pixels in an LCD display since that's already predetermined.