Aspect ratio

Aspect ratio is the proportional relationship between a video’s width and its height, written as two numbers like 16:9 or 9:16. It decides the shape of the frame and, in turn, how a video fits on each screen and platform. A 16:9 ratio is wide and landscape, the classic shape of television and YouTube on a desktop. A 9:16 ratio is tall and vertical, the shape of a phone held upright and the native canvas of Instagram Reels, TikTok, and Stories. A 1:1 square sits in between and was popular for in-feed posts. Choosing the right aspect ratio is not cosmetic: a wide video posted to a vertical feed shrinks to a small band with empty space above and below, killing impact, while a vertical video shot for a phone fills the whole screen and feels native. Compose for the ratio you will publish in, not the one you happened to film in.

Matching ratio to platform

Vertical 9:16 is the default for short-form social. Landscape 16:9 still rules long-form YouTube and embedded site players. If a video needs to live in both places, frame the action in the center so it survives a crop either way.

Planning for the frame

Decide the aspect ratio before you build your shot list, because it changes how you compose every shot. In a vertical frame there is little room left or right, so subjects sit center and motion happens up and down.