Updated June 2026 · runs 100% in your browser

MP4 to MP3

Pull the audio out of MP4 (and MOV, MKV, WebM…) videos as an MP3, right on your device. No upload, no sign-up, no limits.

Drop video files here

or click to choose

🔒 Converted on your device · 0 bytes uploaded

First file loads the converter engine (~25 MB) — after that it’s cached and quick.

How it works

ConvertCabin loads a local copy of FFmpeg — the same engine the big sites run on their servers — compiled to run inside this browser tab. Your media is decoded, converted and saved entirely on your device; nothing is uploaded.

The first conversion downloads the engine (about 25 MB) and your browser caches it, so later conversions start instantly. Because it all runs locally, it stays free, unlimited and private, and works offline once loaded.

About extracting audio

This decodes the audio track from your video and re-encodes it as a standard MP3; the video itself is discarded. It's the quick way to keep just the music, podcast or voice from a clip.

Frequently asked questions

How do I convert MP4 to MP3?
Drop your videos, wait for the engine to load on the first file, and download an MP3 for each. It all runs in your browser.
How long does it take?
It depends on your device and the clip length. The first file also loads the ~25 MB engine; after that, files start right away.
Is my video uploaded?
No. The audio is extracted on your device by a local copy of FFmpeg and never sent to a server.
What is an MP4 file?
MP4 is the most universally compatible video container. It typically holds H.264 video with AAC audio, plays on virtually every device, and balances good quality with reasonable file size.
What is an MP3 file?
MP3 is the most widely supported audio format. Its lossy compression shrinks audio to a fraction of the original size while keeping it perfectly listenable, which is why it became the standard for music.