MP4 to MP3 Converter – Convert MP4 Online (Free Tool)
Extract audio from MP4 videos and convert to MP3 format. High-quality audio extraction for music, podcasts, and more.
Example Output
Audio extracted and re-encoded as MP3 at your chosen bitrate (96-320 kbps). Original video discarded — output is audio-only.
lecture.mp3 (1h20m, 128 kbps stereo, ~73 MB)
What is MP4 to MP3 Converter?
Extract the audio track from any MP4 video and save it as an MP3 — perfect for turning lectures, podcasts, interviews, and music videos into audio-only files you can listen to on a phone, in a car, or in any media player. Runs locally; nothing uploaded.
Why use this tool?
- 100% free with no hidden costs or daily limits
- Works offline after the first page load
- Lightweight page weight that loads quickly even on slow connections
- FFmpeg WASM means the same encoder that powers desktop tools, running in your browser
- First-load downloads the WASM core once (~30 MB), then subsequent edits are fast
How to use
- Upload your MP4 video file
- Select audio quality settings
- Click "Convert to MP3"
- Download the MP3 audio file
Examples
Lecture-as-podcast
A 1h20m university lecture becomes a 73 MB MP3 you can sync to a phone for commute listening.
Interview transcription prep
Strip a 2-hour interview down to audio-only and feed it to a transcription service (Whisper, Otter, etc.) at a fraction of the file size.
Music-video → MP3
Pull the audio out of a music video for your personal listening collection (only for content you own / have rights to).
Common use cases
- Converting lectures and tutorials into podcasts
- Preparing interviews for transcription services
- Listening to video content during commute / exercise
- Reducing storage by keeping only the audio
- Extracting music from concert recordings (own content)
Troubleshooting
- MP3 file is huge
- Lower the bitrate. 128 kbps is fine for spoken word; 192-256 kbps for music. 320 kbps is overkill for most non-music content.
- Output sounds muffled
- Bitrate too low (e.g. 64 kbps). Bump to 128+ kbps. If the source video already had bad audio, MP3 can't fix it.
- Only one channel has sound
- Source was mono with sound on one channel. Toggle "downmix to mono" so the output plays through both channels.
Frequently Asked Questions
Yes, we use high-quality encoding to preserve audio quality during the conversion process.
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