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Glossary · metric

What is Aspect ratio?

Aspect ratio is the proportion of a video frame's width to its height. Common ratios are 16:9 (standard YouTube videos, 1920×1080), 9:16 (Shorts, TikTok), 4:3 (legacy SD content), and 21:9 (cinematic). Mismatched aspect ratios produce letterboxing (black bars) or stretched playback.

Also called:16:9 · 9:16 · vertical video

Standard YouTube videos are 16:9. YouTube Shorts and TikTok are 9:16 (vertical). Cinematic content is often 21:9 ("ultrawide"). The platform supports any aspect ratio at upload — the player simply lets the video fill its native ratio inside a 16:9 viewport, with letterboxing as needed.

When you download a YouTube video, the saved file preserves the original aspect ratio. Software that "converts" aspect ratio either letterboxes (adds black bars) or center-crops (loses content); neither is reversible. Pick the original ratio when you want to keep all the data.

Common questions

Why are YouTube Shorts vertical?
Shorts are designed for mobile-first portrait viewing. The 9:16 ratio fills a phone screen with no rotation needed.

Related terms

Resolution

Resolution is the pixel count of a video frame, expressed as width × height.

FPS (frames per second)

FPS (frames per second) is the number of distinct still images displayed per second of video.

VidPickr is a free, browser-based YouTube downloader. Every term in this glossary either describes how YouTube delivers video or why your downloads behave the way they do. Try the downloader →