What you need to know about monitor size Whether you are upgrading an old monitor, buying one to use with your portable system, or need one to go with a new computer, you'll need to figure out the right size that fits your needs. The portion of the screen you can see is called viewable image size and is an inch or two smaller than the monitor size measurement.
All measurements are diagonal.
If you have a portable computer and simply want a bigger screen to look at for short stretches of time, a 14-inch monitor will suffice. If you are buying a primary monitor or want to view higher resolutions, you will want to step up to at least a 15-inch monitor. The extra inch may not sound like much, but it provides 15 percent more screen area and packs an extra 50 percent more information on the screen. In addition to size, note the monitor's dot pitch, which describes the size of a pixel. Although monitors with large dot pitches, up to 0.40 millimeters, are cheaper, their fuzzy screens can cause eyestrain.