Convert MP4 to MP3
To extract the audio from an MP4 as an MP3, add the video below: ffmpeg in your browser drops the picture and encodes the soundtrack with LAME at high quality (VBR, around 190 kbit/s). Nothing is uploaded.
About converting MP4 to MP3
MP4 (.mp4) files can be converted to MP3 entirely in your browser — no software to install, no file upload, and no account required. The conversion runs on a WebAssembly build of ffmpeg directly on your device.
Common uses
Only convert videos you have the right to use.
- Saving a lecture, interview or podcast recording as audio
- Getting the soundtrack of your own video to edit separately
- Making a smaller file for listening on a phone or in the car
Quality settings used
The audio is encoded with LAME at -q:a 2 (variable bitrate, around 190 kbit/s on average). An MP4's soundtrack is usually AAC, which is already compressed, so this is a second lossy encode — at this setting most listeners can't tell the difference, especially for speech.
Technical comparison
| MP4 | MP3 | |
|---|---|---|
| Category | video | audio |
| Compression type | Lossy (H.264/H.265 video, AAC audio) | Lossy |
| Typical file size | Moderate — a few MB per minute of 1080p video, varying with CRF/bitrate | Small — roughly 1MB per minute at 128–192kbps |
| Transparency support | No | N/A (audio) |
How to convert MP4 to MP3 privately
Every step below runs on a WebAssembly build of ffmpeg inside this browser tab. Your .mp4 file is never uploaded to a server — there's no network request carrying it anywhere.
Add your MP4 file
Drag and drop, or click to select, a file (.mp4). It's read straight from disk into browser memory — no upload step exists.
Convert locally
FreePrivateConvert converts it to MP3 using a WebAssembly build of ffmpeg, entirely within this browser tab.
Download the result
Save your converted .mp3 file. It only ever existed in this tab's memory — closing the tab without downloading discards it completely.
Troubleshooting
- The conversion fails or the MP3 is silent
- The video may have no audio track (screen recordings without sound, for example). Play it with sound first to check.
- Long videos take a while
- The whole file is read before encoding. Audio-only encoding is much faster than video, but an hour-long file still needs a minute or more on most devices.
Convert MP4 to MP3 with ffmpeg (command line)
Prefer the terminal? This is the exact ffmpeg command this page runs for you:
ffmpeg -i input.mp4 -vn -c:a libmp3lame -q:a 2 output.mp3- -i input.mp4
- Your MP4 file.
- -vn
- Drop the video track and keep only the audio.
- -c:a libmp3lame
- Encode the audio as MP3 (LAME encoder).
- -q:a 2
- Variable-bitrate MP3 quality 2 on a 0-9 scale (lower is better; 2 is roughly 190 kbps).
- output.mp3
- The MP3 file to create. ffmpeg picks the container from this extension.
Don't have ffmpeg installed? You don't need it: use the converter at the top of this page. It runs the same conversion on your own device, and your file is never uploaded.
FAQ
- Is my file uploaded anywhere?
- No. Your file is read and processed inside this browser tab and never leaves your device. You can confirm it in your browser's developer tools: the Network tab shows no upload.
- Does converting MP4 to MP3 reduce quality?
- MP3 is lossy and the video's soundtrack was already compressed, so this is a second lossy encode, at LAME's high-quality VBR setting (-q:a 2, around 190 kbit/s). Most listeners won't hear a difference, especially for speech.
- Is there a file size limit?
- Yes: 500MB per file. There's no account and no limit on how many files you convert.
- What's the difference between MP4 and MP3?
- MP4 (MPEG-4 Part 14) and MP3 (MPEG-1 Audio Layer III) store data differently. MP4: lossy (H.264/H.265 video, AAC audio). MP3: lossy. MP3 is the most widely compatible lossy audio format — plays on essentially every device and app made in the last two decades.
- Why convert MP4 to MP3?
- Common uses for MP3: Podcasts and audiobooks; Music distribution and downloads; Extracting audio from video. Universal hardware and software decoder support, making it the safest choice for compatibility.
- What MIME type does a .mp3 file use?
- audio/mpeg, the standard type for MPEG-1 Audio Layer III.
- What is the ffmpeg command to convert MP4 to MP3?
- Run: ffmpeg -i input.mp4 -vn -c:a libmp3lame -q:a 2 output.mp3. This is the exact command FreePrivateConvert runs for this conversion, so you can use this page instead of installing ffmpeg: it runs the same conversion inside your browser.
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