Buying guidance for Displays

A computer monitor is an important part of your computer, as you look or read on it for hours. An energy saving monitor is good for the environment and your wallet, but what features are important for your eyes and comfort?
Below is a description of some features of monitors that can matter in your choice.


Aspect ratio

Aspect ratio describes the shape of the screen being wide or more square. Today most screens are widescreen, having an aspect ratio of 16:9, like flatscreen televisions do. 16:9 means that the width compared to the height of the screen is 16 to 9. Displays with the "old" squarer aspect ratio of 4:3 can still be found, while some professional screens are exactly square (1:1).

Screen size

The screen size of a display is commonly indicated by its diagonal size and measured in inches.

For regular light home use, a 19 inch screen would be usable. When games, photo-editing and video are a more important part of your use, then a larger screen is recommended.


The image on a screen is made up of picture element, or pixels. Two numbers of pixels form the resolution of a display, e.g. 1600 x 900 means the monitor has 1600 pixels in width and 900 pixels in height. On televisions the resolution of 1920 x 1080 is often called "Full HD", a term which is sometimes also used for computer monitors.

Computer monitors offer many choices in resolutions. The higher the numbers, the sharper images and texts can be displayed. Although computer monitors with higher resolutions are more expensive, it is better to choose one with the higher resolution if possible. Eyestrain and fatigue are usually reduced by higher resolution levels. Generally, a 1920 x 1080 pixel monitor is best suited for most situations.
At the moment the highest resolutions are so-called "4K" and "5K". 4K means 3840 x 2160 pixels, while 5K means 5120 2880 pixels. These ultra-high resolution displays are often meant for professional use.


Virtually all new LCD displays can be tilted up or down. For extra flexibility, look for a monitor stand that can be adjusted in height and can swivel without moving the base. This may be especially important if an ergonomic posture has priority.


The main port on a computer monitor is for the video signal. Most computers nowadays use a DVI (digital visual interface) port for this, Others types of video ports are DisplayPort, HDMI, and the older VGA port. Of these ports, only HDMI can be used for both video and audio signals through a single cable, which is useful for monitors with built-in speakers.

Computer monitors can have USB-ports to connect USB-sticks or other equipment with a USB-connection. The monitor by itself can't do anything with the attached USB-devices, but it relays the data-communication to the computer through another (required) USB-cable between the monitor and the computer. Monitors with built-in speakers have a audio jacks to connect to an audio source or headphones. Monitors with a built-in webcam will have a USB-port to send the webcam image from the monitor to the computer.

New, high-end displays provide a USB type-C port to provide power to a laptop and receive video, audio and data, all using a single cable.

Other computer monitor considerations

Response time: The time it takes for a pixel to go from white to black and back to white, measured in milliseconds (ms). A high response time means pixels can't switch fast enough and "ghosting" occurs (e.g., a football flying through the air looks like it has a comet tail). If fast gaming or watching video is important, look for a response time of 5 ms or lower. Such fast monitors however, are less color accurate and have a more limited viewing angle. Monitors that provide high color accuracy and best viewing angles tend to be slower (e.g. 12 ms).

Refresh rate: How many times a display can update the picture in a second, measured in hertz (Hz). Standard monitors refresh at 60 Hz. A monitor with a faster refresh rate, usually 120 Hz, can make things like scrolling look more fluid.

Contrast ratio: The difference between the brightest white and the deepest black. E.g., a contrast ratio of 1000:1 means its brightest white is 1000 times brighter than its deepest black. A higher contrast ratio can produce images that are more vivid and punchy. However, because the way manufacturers measure contrast ratio is not uniform, advertised figures are not reliable.

Viewing angle: The angles a monitor can effectively be viewed at, measured in degrees (e.g. 170). Older flatscreen monitors typically had narrow viewing angles, but newer models seldom present a problem to viewers, making it less of an important factor. However, many displays of notebooks have a more limited viewing angles, mostly because such displays are cheaper.

Brightness: How much light a monitor can emit, measured in candelas per square meter (cd/m). A brightness of 250 to 300 cd/m is common for most monitors. A bright screen is important if you're working in a brightly lit environment.

LED backlighting: LED monitors are simply LCD monitors that use an LED backlight. LEDs allow manufacturers to make monitors slimmer, brighter, more energy-efficient and without the warm-up time of traditional compact fluorescent (CCFL) backlights. Nowadays virtually all LCD monitors have LED backlighting.

Glossy or matte screen: Depending on lighting conditions, the LCD screen coating can make a huge difference. Glossy screen coatings tend to enhance contrast for a more vibrant look, but also reflect more of their surroundings when displaying a darker image. Matte monitors displays tend to look duller, but do not reflect much and are therefore more usable in bright environments or across large windows. Monitors aimed for office work typically have matte screens.

Touch screen: A screen with touch sensitivity, allowing you to control the computer through touching the display. With Windows 8 and continued in Windows 10, computers with touch screens are becoming more prevalent.


The above information is based on the buying guidance of the USA EPA ENERGY STAR website.

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