· The first conversion downloads the FFmpeg engine (about 32 MB). It is cached afterwards.
· Keep files under 2 GB, and under a few hundred MB if you are on a phone or re-encoding video.
· Keep this tab in the foreground — browsers throttle background tabs and the conversion will pause.
How to convert WEBM to MP3 in 3 steps
1
Add your WEBM file
Drop in a .webm file — typical sources are browser recordings, webinar captures and downloaded web video.
2
Set the bitrate
192 kbps is the default and matches most web audio. Go to 320 kbps if the source audio is high quality music.
3
Extract the audio
Press Convert. The Opus or Vorbis audio inside the WEBM is decoded and written out as MP3.
About WEBM and MP3
What is inside a WEBM file
WEBM is a container Google designed for the open web. It wraps VP8, VP9 or AV1 video together with Vorbis or Opus audio. Browsers love it, but desktop players, phones and editors are much less consistent — which is why a WEBM that plays perfectly in Chrome may refuse to open in a media player or a video editor.
Audio extraction versus full transcoding
This tool discards the video stream entirely, so the VP9 or AV1 video is never decoded and no CPU is spent on pixels. Only the audio track is decoded and re-encoded to MP3. That makes the conversion quick even for long recordings, and the output is a fraction of the original size.
Where WEBM recordings come from
Browser-based screen and tab recorders, webinar platforms, Google Meet and similar tools can export or download in WEBM. Lecture recordings, conference talks and online courses are the most common sources. If you only need the spoken content, an MP3 is far easier to carry around than a video file.
Frequently asked questions
How do I convert WEBM to MP3 for free?
Add the WEBM file at the top of the page, pick a bitrate and press Convert. It is free, requires no account and leaves no watermark.
Does the video get converted too?
No. The tool extracts the audio track and discards the video stream, which is why the output is a small MP3 instead of a video file.
The WEBM plays in my browser but not in my player — why?
WEBM is a web-first format. Many desktop players and mobile devices do not support VP9 or Opus. Converting to MP3, or to MP4 for video, solves that.
Can I convert a WEBM with Opus audio?
Yes. Opus audio inside WEBM is decoded and re-encoded to MP3 normally. Note that both Opus and MP3 are lossy, so a small quality change is expected.
What is the maximum file size?
About 2 GB, limited by the 32-bit memory WebAssembly runs in. Long screen recordings in the hundreds of megabytes are fine.
Is anything uploaded to your servers?
No. Your browser reads the file and converts it on your own machine. Nothing leaves your device.
More conversions
Every tool below runs in your browser with the same no-upload guarantee.