Video Converter — MP4, WebM, MOV, MKV
Change a video’s format — between MP4, WebM, MOV and MKV — right in your browser. Pick a target format and download the converted file. Your video is never uploaded.
How to use it
- 1Choose a video
Drop a video onto the drop zone, or click to select one.
- 2Pick a format
Choose MP4, WebM, MOV or MKV as the output.
- 3Convert
Click Convert. The first run loads the converter (~30 MB) once.
- 4Download
Preview the result in the page, then download it. Nothing was uploaded.
Pick the right container
MP4 (H.264) is the most compatible choice and plays almost everywhere. WebM (VP8/Vorbis) is great for the web. MOV suits Apple workflows, and MKV is a flexible container for archiving. Convert to whichever a device or site needs.
Runs on your device
Conversion uses a WebAssembly build of ffmpeg that runs inside the page, so the file never leaves your device. Because it re-encodes the video, it works best on short clips; the first run loads the converter (~30 MB) once.
Frequently asked questions
Is my video uploaded to a server?
No. Conversion happens entirely in your browser with a WebAssembly build of ffmpeg — your video never leaves your device.
Which formats can I convert between?
MP4 (H.264/AAC), WebM (VP8/Vorbis), MOV and MKV. Most common video inputs are accepted.
Why does the first conversion take a moment?
The in-browser converter (~30 MB) downloads once on first use, then is cached for the session.
Is there a size or length limit?
Because it runs in your browser, very large or long videos can be slow and memory-heavy. Short clips convert best.
Related tools
Compress Video
Make a video smaller in your browser — pick a quality level and download a compressed MP4. No upload, no sign-up; your video never leaves your device.
Mute Video
Remove the audio from a video in your browser without re-encoding — fast and lossless. No upload, no sign-up; your video never leaves your device.
Video to MP3
Extract the audio from a video as an MP3, right in your browser. Choose the bitrate, then download. No upload, no sign-up — your video never leaves your device.