VIDEO CONVERTER
Video converter, MP4 to WebM in a click.
Convert between MP4, WebM, MOV, AVI and MKV, with resolution, frame rate and quality control. Runs locally in your browser, nothing uploaded.
Drop or choose a video
MP4 / MOV / AVI / MKV / WebM supported; up to ~300MB recommended
Output settings
File info
Format tips
MP4 has the widest compatibility and suits phones and social media; WebM is smaller and good for web embedding; MOV fits editing software; MKV suits archiving and multi-track audio; AVI works on old devices but tends to be large.
Everything runs locally in your browser
What can this tool do?
Convert videos between MP4, WebM, MOV, MKV and AVI — e.g. MP4 to WebM to shrink the file, WebM to MP4 for phone compatibility, or AVI to MP4 for modern players. Choose output resolution (4K down to 360p), frame rate (60/50/30/24/15) and quality CRF, and optionally strip the audio track. The right panel shows the source duration, resolution and size so you can compare before and after. Everything runs locally; the video never leaves your device.
FAQ
What is CRF and how do I choose it?
CRF is the constant-quality factor: lower means better quality and a bigger file. Around 18 is near visually lossless, 23 is the balanced default, 28 shrinks the file noticeably, and above 32 quality loss becomes visible. For everyday sharing, 26-30 works well.
Why is the first run slow?
Conversion uses the in-browser ffmpeg engine, which downloads about 30MB once and is then cached. Longer and higher-resolution clips also take longer, so try a short excerpt first.