MP4 to MP3

Extract MP3 audio tracks from MP4 video files in the browser.

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Quick Tip

Select the .mp4 file you want the audio from.

About This Tool

Why use MP4 to MP3?

Pull the audio out of an MP4 and save it as an MP3 at 192 kbps. FFmpeg runs in your browser as WebAssembly with the video stream discarded, so only the soundtrack is encoded — which is why this is far quicker than a full video conversion and why the file comes out a fraction of the size.

192 kbps is the bitrate most people settle on for spoken content and general listening: transparent enough that the difference from the source is inaudible in normal conditions, small enough that an hour of audio is around 85 MB. Nothing is uploaded, which matters more here than for most conversions — recorded lectures, interviews, meetings and unreleased music are exactly the material you would not want to hand to a conversion site.

Key Benefits

192 kbps output

High enough to be transparent for speech and general listening, while keeping an hour of audio to roughly 85 MB.

Video discarded, not re-encoded

The video stream is dropped rather than processed, so the conversion is far faster than a full transcode.

Nothing leaves your device

FFmpeg runs inside the tab, so lectures, interviews and unreleased recordings are never uploaded anywhere.

How to use MP4 to MP3

1
Select the .mp4 file you want the audio from.
2
Convert; FFmpeg loads in the tab, then discards the video and encodes the audio at 192 kbps.
3
Watch the progress — the first run takes a moment while the FFmpeg core loads.
4
Download the MP3.

Best use cases

Get the audio from a recorded lecture or webinar to listen to offline.

Extract an interview's soundtrack for transcription.

Turn a video podcast into an audio file for a phone.

Keep just the audio from a meeting recording and drop the video weight.

MP4 to MP3 FAQs

Why does the first conversion take longer to start?

The FFmpeg WebAssembly core has to load into the tab first — it is around 32 MB. After that it stays loaded, so subsequent conversions start immediately.

What bitrate is the MP3?

192 kbps constant. That is transparent for speech and general listening, and works out at roughly 85 MB per hour of audio.

Is my video uploaded?

No. The conversion runs entirely in your browser using WebAssembly, so the file never leaves your computer.

Why did a large file fail?

A browser tab has a memory ceiling that a desktop application does not. Very large or long videos can exhaust it. Trim the file first, or use a desktop tool for multi-gigabyte recordings.