Remember that resolution is not a clean indicator of size of the monitor but it does place some limits on what the size could be.

The table below is from the Computing Suppliers Federation (an industry group of monitor manufacturers). Some may be happy with a resolution that is outside the ranges quoted, but many users would not. It is unlikely that combinations outside this range would meet ISO 9241/3, the major international standard for monitor ergonomics.

Monitor Nominal Size	Typical Image Size	Minimum Resolution	Maximum Resolution
14"	12.3"-13"	640x480	800x600
15"	13.5"-14"	640x480	1024x768
17"	15.5"-16"	800x600	1280x1024
19"	17.5"-18.1"	1024x768	1280x1024
20"/21"	19"-20"	1024x768	1600x1200
24"	21"-22"	1600x1000	1920x1200

Here is another reference:http://www.proaxis.com/~ferris/docs/dpi-monitor.html