How to convert MP4 to MP3
- Choose one or more MP4 files, or drop them on the page.
- Check that Format shows MP3 audio and pick a bitrate (192 kb/s is the default).
- Select Convert to MP3 audio.
- Download each MP3, or all of them as a ZIP.
Worked example
In the converter's automated test, a 1-second 1280×720 video named hd.mp4 becomes hd.mp3. ffprobe reads it as MP3 audio with no video stream, and the file list notes the sound as MP3 (re-encoded).
Formats and limits
| Input | MP4, MOV, M4V, WebM, MKV, MPEG-TS |
|---|---|
| Output | MP3 |
| Limits | Input files up to 4 GB are read in pieces; the converted file is built in memory, so outputs above about 2 GB may fail. Needs a browser with WebCodecs (current Chrome, Edge, Safari 17+ or Firefox 130+). Other browsers are told so before any work starts. |
| Engine | Mediabunny (WebCodecs): streams are copied when compatible, otherwise re-encoded; MP3 via a WebAssembly encoder |
Limitations
- The sound is re-encoded, so the MP3 cannot sound better than the audio in the video.
- Surround sound is mixed down to stereo.
- A video without a sound track cannot be converted to MP3; the file list says so.
- Needs a browser with WebCodecs: current Chrome or Edge, Safari 17 or later, or Firefox 130 or later. Other browsers are told so before any work starts.
Questions
Is it safe to convert MP4 to MP3 online?
On this page the conversion runs in your browser. The video is read from your device and the MP3 is built in memory; nothing is uploaded to a server.
Which MP3 bitrate should I choose?
192 kb/s is the default and suits most music and speech. 320 kb/s is the highest MP3 bitrate offered; 96 or 128 kb/s gives smaller files for spoken word.
Can I convert several MP4 files at once?
Yes. Add up to 50 videos; each becomes its own MP3 with the same name, and you can download them one by one or together as a ZIP.
Privacy
Runs on your device. Files and text are processed in this browser tab and are not uploaded.
This page opens the Video format converter ready for this task. See the privacy policy for how toolsdocks handles data.