Convert MP4 to MP3 Online — No Upload, Private
Extract audio from MP4 videos and convert to MP3 format. All processing happens in your browser. Files never leave your device. No sign-up required. Also supports decrypting NetEase NCM, QQ Music QMC, Kugou KGM encrypted music formats.
Try it Now →Why Choose Formavide?
- Privacy First: Most tools run locally in your browser. GPU features use encrypted cloud processing with auto-delete.
- No Sign-Up: Open your browser and start. No account needed.
- Free to Use: Basic features are always free.
- Cross-Platform: Chrome, Edge, Safari, and mobile.
How to Use
- Open the tool page.
- Upload your file.
- Adjust settings.
- Click start.
- Download the result.
FAQs
Do I need to upload files for MP4 to MP3 conversion?
No. Everything happens in your browser. Your files never leave your device.
What audio quality can I expect?
Supports up to 320kbps MP3 bitrate, suitable for most use cases.
What is the maximum file size?
Files up to 500MB are supported.
Is MP4 to MP3 conversion free?
Local conversion is completely free and unlimited. Very large files can switch to cloud GPU conversion for a few credits — the estimate shows before upload.
Does it work on mobile?
Yes. Open the page in a mobile browser and convert small files directly; for large or batch jobs, desktop is faster.
What Actually Happens During MP4 to MP3 Conversion
MP4 is a container: it packages a video stream, an audio stream, and optional subtitles into one file. Extracting MP3 means pulling the audio stream out and encoding it as MP3.
If the source audio is already MP3, it can technically be stream-copied without re-encoding. In practice most sources use AAC, so one re-encode is needed. Output quality depends on your chosen bitrate — 320kbps is transparent for almost all listening.
Choosing the Right Bitrate: 128 vs 192 vs 320 kbps
Rule of thumb: your source sets the ceiling. Re-encoding a 96kbps AAC source at 320kbps won't sound better — just bigger. 192kbps suits typical phone videos; use 320kbps for music content.
| Bitrate | Size per Minute | Best For |
|---|---|---|
| 128 kbps | ~1 MB | Voice memos, meeting recordings, podcasts |
| 192 kbps | ~1.4 MB | Everyday music listening, background audio |
| 320 kbps | ~2.4 MB | Music collections, quality-critical uses |
Common Use Cases
- Podcast/interview videos → listen on the commute
- Lecture recordings → audio-only revision, saves battery and storage
- Music videos/concert footage → add songs to playlists
- Meeting screen recordings → audio prep before speech-to-text
Why In-Browser Conversion Beats Upload Sites
- Privacy: your video never touches a server — private footage stays private
- Speed: no upload/download queues, even for 500MB files
- Cost: local conversion is completely free, unlimited
- Works on phone, tablet, and desktop browsers alike