Video converter
Turn almost any video into MP4, WebM, MOV or MKV, with the quality you choose, without sending it anywhere.
Sealed on this device
Runs in your browser. Nothing is uploaded.
Sealed
Your video
Your browser can’t play this format, but the file can still be processed.
Result
- Original
- New file
- Saved
How it works
-
Add your video
Drop a video or choose one from your device. It is opened right in your browser and never uploaded.
-
Pick the format
Choose MP4, WebM, MOV or MKV and a quality level. Keeping the original streams makes it nearly instant when the codecs allow it.
-
Convert and download
Follow the progress, then preview and download the converted video.
Frequently asked questions
Is my video uploaded to a server?
No. The conversion runs inside your browser with a WebAssembly version of FFmpeg. Your video stays on your device from start to finish.
Which format should I choose?
MP4 (H.264 video, AAC sound) plays on almost every phone, computer, TV and website, so it is the safest choice. WebM suits web pages, MOV is handy for Apple editing apps, and MKV for media players.
Why is the conversion sometimes instant?
When the video and sound already use codecs the new format accepts, the tool copies them into the new container instead of re-encoding them. That takes seconds and loses no quality. Untick the option to force a full re-encode.
Why is it slower than a desktop app?
Your browser runs the converter in a protected sandbox and can’t use the graphics chip’s video encoder, so long or 4K videos take a while. A modern computer with several cores is noticeably faster than a phone.
Is there a file size limit?
There is no limit set by us, but browsers struggle with files over about 2 GB, and the result has to fit in your device’s memory. For very large videos, trim or compress them first.
Which open-source software does this tool use?
It uses FFmpeg compiled to WebAssembly by the ffmpeg.wasm project (github.com/ffmpegwasm/ffmpeg.wasm). Its core is licensed under the GPL, and its full source code is available from that project.