What Is a Monitor?

Monitor definition, facts, and troubleshooting guides

Dell UltraSharp UP3017Q 30-Inch OLED Monitor


The monitor is the piece of computer hardware that displays the video and graphics information generated by the computer through the video card.

Monitors are very similar to televisions but usually display information at a much higher resolution. Also unlike televisions, monitors are not usually mounted on a wall but instead sit atop a desk.

Other Names of a Monitor

A monitor is sometimes referred to as a screen, display, video display, video display terminal, video display unit, or video screen.

A monitor is sometimes incorrectly referred to as the computer, as in the hardware within the computer case, like the hard drive, video card, etc. For example, shutting down the computer isn't the same thing as turning off the monitor. It's important for that distinction to be made.

Important Monitor Facts

A monitor, no matter the type, usually connects to either an HDMI, DVI, or VGA port. Other connectors include USB, DisplayPort, and Thunderbolt. Before investing in a new monitor, make sure that both devices support the same type of connection.

For example, you don't want to buy a monitor that has only an HDMI port when your computer is capable of accepting only a VGA connection. Although most video cards and monitors have multiple ports so as to work with various kinds of both devices, it's still important to check their compatibility.

Adapter to connect a VGA cable to an HDMI computer

If you do need to connect an older cable to a newer port (e.g., HDMI to VGA) — like if you're using a monitor that has a VGA connection, with a computer that uses HDMI — there are adapters for this very purpose.

Monitors are not typically user serviceable. For your safety, it's not usually wise to open and work on a monitor.

Popular Monitor Manufacturers

The following are some of the most popular brands of computer monitors available for purchase: Acer, Hanns-G, Dell, LG Electronics, Sceptre, Samsung, HP, and AOC.

You can also purchase monitors from these manufacturers and others through retailers like Amazon and Newegg.

Monitor Description

Monitors are display devices external to the computer case and connect via a cable to a port on the video card or motherboard. Even though the monitor sits outside the main computer housing, it is an essential part of the complete system.

Monitors come in two major types — LCD or CRT, but others exist, too, like OLED. CRT monitors look much like old-fashioned televisions and are very deep in size. LCD monitors are much thinner, use less energy, and provide a greater graphics quality. OLED is an improvement on LCD that provides even better color and and viewing angles but also requires more power.

LCD monitors have completely obsoleted CRT monitors due to their higher quality, smaller "footprint" on the desk, and decreasing price. OLED, although newer, is still more expensive and therefore not as widely used when it comes to monitors in the home.

Samsung LC49HG90DMNXZA CHG90 Series Curved 49-inch Gaming Monitor

Most monitors are in a widescreen format and range in size from 17 inches to 24 inches, but others are 32 inches or more, some even much wider like the gaming monitor above. This size is a diagonal measurement from one corner of the screen to the other, not including the outer casing (the part that has the manufacturer name, physical buttons, etc.).

Monitors are built-in as part of the computer system in laptops, tablets, netbooks, and all-in-one desktop machines. However, you can buy one separately if you're looking to upgrade from your current monitor or configure a multi-monitor setup.

Although monitors are considered output devices since they usually only serve the purpose of outputting information to the screen, some of them are touch screens as well. This type of monitor is considered both an input and output device, which is usually called an input/output device, or an I/O device.

Some monitors have integrated accessories like a microphone, speakers, camera, or USB hub.

More Information on Monitors

Are you dealing with a monitor that isn't showing anything on the screen? Read our guide on How to Test a Computer Monitor That Isn't Working for steps that involve checking the monitor for loose connections, making sure the brightness is properly set, and more.

Newer LCD monitors should be cleaned with care and not like you would a piece of glass or older CRT monitor. If you need help, see How to Clean a Flat Screen TV or Computer Monitor.

Read How to Fix Discoloration & Distortion on a Computer Screen if your monitor doesn't seem to be displaying things like it should, like if the colors seem off, the text is blurry, etc.

If you have an older CRT monitor that has a problem displaying colors, like if you see an array of colors around the edges of the screen, you need to degauss it to reduce the magnetic inference that's causing it. See How to Degauss a Computer Monitor if you need help.

Screen flickering on a CRT monitor can be solved by changing the monitor's refresh rate, something you can do from the Windows Control Panel.

Monitors are usually instantly available through plug and play. If the video on the screen doesn't appear as you think it should, consider updating the video card driver. See How to Update Drivers in Windows if you need help.

The performance of a monitor is usually determined by a number of factors and not just one feature like its overall screen size, for example. Some of these include the aspect ratio (horizontal length against the vertical length), power consumption, refresh rate, contrast ratio (ratio of the brightest colors vs the darkest colors), response time (the time it takes a pixel to go from active, to inactive, to active again), display resolution, and others.