Over the past few years, the most popular televisions have been 720p, 1080p, and 4K. If we look at the terms we're using to describe them, it's clear to see that a video created in 720p has 1,280 columns and 720 rows of pixels, giving it 921,600 pixels of resolution and clarity. For a long time, that was the industry standard and was completely acceptable for people purchasing TVs or recording videos with the highest possible clarity.
1080p, again using the terms discussed, consists of 1,920 columns and 1,080 rows of pixels for a total of 2,073,600 pixels, over double that of a 720p video. This really upgraded what was possible in video recording and viewing, and created a new standard for what people were looking for in their monitors and video.
Then we have 4K. Because the most common way of describing 4K differs from the 720p and 1080p format, it becomes a little more confusing about what 4K actually entails. In reality, 4K could also be described as 2160p, because it contains 3,840 columns and 2,160 rows of pixels. With that in mind, we can tell that 4K is clearly the highest level of resolution, made up of 8,294,400 pixels, four times as many pixels as 1080p. In addition to 4K or 2160p, you may see this resolution also referred to as Ultra HD or UHD.
Though 4K was once so costly that normal consumers weren't able to purchase it, the price has come down to a more reasonable standard and video shot in 4K can now be readily viewed by more people.