Resize Video Online

About Resize Video Online

Reducing a video's resolution — to shrink file size, meet a platform's upload dimensions, or match a specific display size — is a common need distinct from cropping (which removes content) or compressing (which reduces bitrate at the same resolution). This tool changes the actual pixel dimensions while automatically preserving the original aspect ratio.

You set only the target width; height is calculated automatically to keep the video's original proportions exactly intact, so there's no risk of accidentally stretching or squashing the picture out of shape by entering a mismatched height yourself.

A real FFmpeg build compiled to WebAssembly performs the resize entirely inside your browser using the scale filter, with the height dimension set to automatically round to the nearest even number — a technical requirement of the H.264 codec, handled transparently so the encode doesn't fail on an odd height value.

Resizing to a smaller width is one of the most effective ways to reduce file size, since fewer total pixels means significantly less data to encode per frame — often a bigger size reduction than compression settings alone can achieve without visible quality loss.

How it works

1. Upload your video. The file loads into the browser-based FFmpeg engine.
2. Set the target width. Height scales automatically to preserve aspect ratio.
3. Resize and download. A re-encoded video at the new dimensions.