Resize video

No. The conversion runs entirely in your browser. The file never leaves your device – there is no server that could see it. Once the page has loaded, the tool even works offline.

The video is encoded on your own device with FFmpeg compiled to WebAssembly, which is several times slower than a native program. Expect roughly one to three minutes per minute of 720p video on a laptop, more on a phone. Short clips are the sweet spot; for a two-hour film use a desktop program. The engine (about 32 MB) is downloaded once per visit.

1280 pixels wide (720p) is a good all-rounder for the web and messaging; 854 (480p) for small previews; 1920 (1080p) only if the source is larger. Videos are never enlarged unless you switch on “Allow enlarging” – upscaling adds no detail, only file size.

Yes, the picture has to be – with H.264 for MP4, MOV, MKV and AVI and VP8 for WebM, at a quality where the loss is hardly visible. The audio track is copied unchanged.

Files up to 300 MB are accepted, and a job is stopped after ten minutes. The whole file has to fit into the browser's memory, so clips of a few minutes work best. If processing stops, trim the clip first or lower the resolution.

We remove the file's global metadata, including the recording location an iPhone stores in MOV and MP4 files. Rotation information is applied, so the video keeps its orientation.