What Is 4K / UHD Resolution? A Basic Definition

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4K, also known as 2160p and UHD, is a popular display resolution. Resolution explains how many pixels a display has in width x height format. The more pixels a screen has, the sharper its image should look. The Digital Cinema Initiatives (DCI), a group of motion picture studios that creates standards for digital cinema, defines 4K resolution as 4096 x 2160, but this resolution is rare in consumer products. You'll usually see PC monitors, laptops and TVs labeled as 4K have a 3840 x 2160 resolution. However, this resolution is officially considered Ultra HD (UHD). You'll often see displays labeled as 4K/UHD.

Most modern GPUs support 4K/UHD output, though you'll need a reasonably powerful graphics card to play games at this resolution. For this reason, many gamers prefer running games at 1080p resolution (1920 x 1080).

There are numerous high-end laptops with 4K screens available. There are also a lot of 4K monitors on the market today, and they can be relatively affordable. However, if you want a 4K gaming monitor with a high refresh rate (120Hz or greater), you'll have to pay a premium. 

Common PC Display Resolutions

Swipe to scroll horizontally
5K5120 x 2880
4K3840 x 2160 (typical monitor resolution); 4096 x 2160 (official cinema resolution)
Ultra HD (UHD)3840 x 2160
QHD aka WQHD aka 1440p2560 x 1440
2K2560 x 1440 (typical monitor resolution); 2048 x 1080 (official cinema resolution)
WUXGA 1920 x 1200
Full HD aka FHD aka 1080p1920 x 1080
HD aka 720p1280 x 720

This article is part of the Tom's Hardware Glossary.

Further reading:

Scharon Harding

Scharon Harding has a special affinity for gaming peripherals (especially monitors), laptops and virtual reality. Previously, she covered business technology, including hardware, software, cyber security, cloud and other IT happenings, at Channelnomics, with bylines at CRN UK.

  • Findecanor
    What happened was that the TV industry was supposed to release a 4K format: a real 4K format, with 4096 pixels horizontal resolution like the DCI standard.
    This got a lot of interest in the enthusiast press.
    Then the industry's standards body changed its mind, to instead double the resolution from Full HD.
    But enthusiasts had followed the development... and to make it clear for them that the new "Ultra HD" format was what had come out of the "4K" development, some TV manufacturers, first among them being Sony, started to market their Ultra HD televisions as "4K".

    The monikers "4K UHD" and "4K/UHD" came about as a way to avoid confusion between real 4K and UltraHD.

    Note also that there has never been any similar conflation between the DCI standard "2K" and the TV standard "Full HD" ... or at least not before "4K UHD" happened.

    It could also be discussed whether computer screens should adopt marketing terms used to sell televisions.
    Real computer screens with an actual horizontal video resolution of 4096 pixels do also exist, e.g. in 21.5" iMacs (last Intel based), and some monitors from Eizo among others.