Viewable image size

On a computer monitor, the viewable image size or VIS is the actual amount of screen space that is available to display a picture, without obstruction from the case or other aspects of the unit's design.

On cathode ray tube monitors, VIS differs noticeably from the full tube size, which is generally about 25mm or one inch larger.

Liquid crystal displays use 100% of their surface to display, thus the VIS is the actual size presented to the viewer.

In the U.S., manufacturers and retailers are allowed to list the tube size, which is misleading and confusing to many customers, especially when comparing both CRT and LCD models together. In many other countries, this practice is prohibited by consumer-protection laws.

The viewable image size (often measured in inches or millimeters) is sometimes called the "physical image size", to distinguish it from the "logical image size" ( display resolution ) (measured in pixels) of various computer display standards.

Further confusion can result from listing the diagonal measurement of a monitor, as the actual viewable area is also dependent on the aspect ratio of the monitor. Below is a helpful chart of some common sizes of LCDs with varying aspect ratios and their actual viewable area.

If the diagonal is D, and the aspect ratio is W:H then the dimensions can be calculated as follows:

$height=sqrt\{frac\{D^2*H^2\}\{W^2+H^2$

$width=frac\{W\}\{H\}*height$