Drop a video above and download its soundtrack as an MP3. The audio is encoded at 192 kbps with ffmpeg running on your device, so even private recordings never leave your computer or phone.
Why convert MP4 to MP3?
Keeping only the audio makes a file far smaller and lets you play a talk, lecture, interview or song on any music player, in the car or as a podcast, without the picture.
How it works
1. Drop an MP4 — MOV, WebM, MKV and other common videos work too.
2. The audio track is decoded and encoded to MP3 (LAME, 192 kbps) by ffmpeg compiled to WebAssembly.
3. The MP3 downloads with “-audio” added to the original file name. Short clips take seconds; long videos take longer because the whole file is processed on your device.
MP4 vs MP3
MP4: a container holding video (usually H.264 or H.265) and audio (usually AAC). Large because of the picture.
MP3: audio only, plays on essentially every device. At 192 kbps it takes about 1.4 MB per minute — a tiny fraction of the video.
Quality notes
The video’s audio is usually AAC, so creating an MP3 is a lossy-to-lossy step; at 192 kbps the difference is not audible for speech or casual music listening. The original video is not changed.
Common use cases
Turning recorded lectures and meetings into audio for your commute; saving the music from your own video; sending a voice recording that was captured with a phone camera; transcribing speech (the MP3 can then go to Audio to Text).
Frequently asked questions
What bitrate is the MP3?＋
192 kbps — a good balance for music and more than enough for speech.
Does it work with MOV, WebM and MKV?＋
Yes. ffmpeg reads most common video containers, not just MP4.
What if the video has no sound?＋
You will see a message that there is no audio track to extract.
Can I use it on a phone?＋
Yes, in Safari or Chrome. Very long videos need more memory, so a computer is faster for hour-long files.
Can I cut out just part of the audio?＋
Convert first, then use Audio Trim on the MP3 to keep the section you want.