MP4 to MP3
Extract and encode a real MP3 audio file from any MP4, MOV, or WebM video — 128 kbps, entirely in your browser. No upload required.
Drop files here, browse
Drop an MP4, MOV, or WebM video
Max file size: 100 MB
Real MP3 Output
Audio is encoded to MP3 at 128 kbps using the LAME algorithm running directly in your browser — no server involved.
Fully Private
Your video file never leaves your device. Audio is decoded with the Web Audio API and encoded to MP3 locally.
Stereo & Mono
Stereo and mono sources are handled correctly. Files with more than 2 channels are downmixed to stereo (front left + right).
How to convert MP4 to MP3
- Drop your MP4, MOV, or WebM video onto the upload area above.
- Click Convert to MP3. The audio is decoded and encoded to MP3 in your browser.
- Wait for encoding to finish — larger files take longer. A progress bar shows the status.
- Click the download button to save your
.mp3file.
About the output
Audio is encoded to MP3 at 128 kbps using the LAME algorithm running entirely in your browser. This bitrate is suitable for music, podcasts, and voice recordings. Stereo sources are preserved as stereo; mono sources are encoded as mono. If your video has more than two audio channels (e.g. 5.1 surround), only the front-left and front-right channels are used.
Encoding time depends on file length and your device's speed. A 5-minute MP4 typically takes 2–10 seconds on a modern desktop and up to 30 seconds on mobile. Very large files (over 150 MB) may take longer and the page may feel briefly unresponsive while the encoder runs — this is normal and no data is being uploaded.
Privacy — your files stay on your device
This tool uses the browser's Web Audio API to decode the video's audio track and the LAME MP3 encoder (running as JavaScript) to produce the MP3 file. Your video file is never uploaded to any server. Everything happens locally on your device.
Frequently Asked Questions
Is this tool free?
Yes — completely free. No account, no signup, no limits on how many files you convert.
Is my video uploaded to a server?
No. All processing happens in your browser using the Web Audio API and a JavaScript MP3 encoder. Your file never leaves your device.
What video formats are supported?
MP4, MOV, and WebM are the best-supported formats. AVI may also work depending on your browser. Support depends on what codecs your browser can decode natively.
Why does it take a while for large files?
MP3 encoding requires processing every audio sample. For a long video, this involves millions of calculations running in JavaScript. The page may feel unresponsive briefly — no data is being uploaded.
Does it work on mobile?
Yes — any modern browser on iOS, Android, Mac, Windows, or Linux works. Encoding will be slower on older or lower-powered devices.
My file failed to convert — why?
The Web Audio API must be able to decode the video's audio codec. Very old or unusual codecs (some AVI files, DRM-protected content) may not be supported by your browser. Try a different browser or re-encode the source file first.