In a nutshell, 4K refers to approximately 4 times the maximum resolution of current high-definition (HD) displays. Today’s hi-def displays top out at 1080 x 1920 pixels of resolution, often referred to as “1080P”. At this time, there’s no agreed upon standardized definition of 4K (therefore the “approximately” 4x resolution). The HDMI organization (the people who set the specs for the popular HDMI audio/video cable in use today) recently added two of the 4K formats to its latest specification: “Quad HD” (3840 x 2160 pixels) and 4K/2K, also called 4K x 2K (4096 x 2160 pixels). Quad HD matches the 16:9 ratio (screen shape) of modern television screens.4K video resolution comparison

The graphic here shows proportionally the amount of picture information in various formats. You can quickly see how much more picture information there is with the “4K” formats. Four times the resolution sounds amazing, and it does provide the clearest details we’ve ever seen, but for most people this doesn’t really become noticeable unless you’re either sitting very close to the screen or if your screen is very large (more than 80″).

That’s 4k in a nutshell.