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Video glossary

What is Resolution?

Definition

Resolution is the pixel dimensions of a video frame, written as width x height (for example 1920x1080). More pixels mean a sharper, more detailed image, but also a larger file.

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A video's resolution counts the pixels in each frame, written as width by height. Common sizes are 1280x720 (720p, HD), 1920x1080 (1080p, Full HD), and 3840x2160 (4K or UHD). So 1920x1080 means 1920 pixels across and 1080 down. Together these numbers define how much detail a single frame can hold.

Higher resolution packs more pixels into the frame, making the picture look sharper, especially on large screens. The trade-off is size: a 4K frame has about four times the pixels of 1080p, so it needs far more storage and a faster connection to stream. The right resolution depends on the screen and how the video is delivered.

Resolution is often confused with two related terms. Aspect ratio describes the frame's shape (such as 16:9 or 9:16), not its pixel count. Bitrate is the amount of data per second; a high-resolution video at a low bitrate can still look blocky, because the two settings control different things.

Quick facts

  • Written as width x height in pixels, e.g. 1920x1080
  • 720p = 1280x720, 1080p = 1920x1080, 4K/UHD = 3840x2160
  • More pixels mean a sharper image and a larger file
  • 4K has about four times the pixels of 1080p
  • Different from aspect ratio (the shape) and bitrate (the data rate)

Frequently asked questions

What does 1080p mean?
1080p is a resolution of 1920x1080 pixels, also called Full HD. The 1080 is the number of horizontal lines (the frame height), and the p stands for progressive scan, where each frame is drawn in full rather than in interlaced halves.
Is higher resolution always better?
Not always. Higher resolution gives a sharper image but creates much larger files and needs more bandwidth to stream. On a small phone screen the difference between 1080p and 4K can be hard to notice, so the best choice depends on the screen size and use case.
What is the difference between resolution and aspect ratio?
Resolution is the exact pixel count of the frame (like 1920x1080), while aspect ratio is the frame's shape, such as 16:9 or 9:16. Two videos can share the same aspect ratio but have very different resolutions.
Does resolution affect file size?
Yes. More pixels mean more data, so higher resolution generally produces larger files. Bitrate and codec also affect size, but at the same settings a 4K clip will be much bigger than a 1080p one.

Related tools

Change Video ResolutionOnline Video CompressorAspect Ratio Calculator

Related terms

Aspect RatioBitrateFrame Rate