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Browser-local media conversion

MP4 to MP3 Converter

Extract and convert an MP4 file's audio track to MP3 locally. No file upload, server conversion, or paid conversion API.

Processed locally

Your media file is processed in this browser and is not uploaded to our servers.

Drop your MP4 file here

or choose one from your device

Maximum 100 MiB · processed locally

How it works

Local conversion in four clear steps

  1. 1

    Choose a file

    Select a MP4 file up to 100 MiB from your device.

  2. 2

    Choose bitrate

    Select a supported constant MP3 bitrate.

  3. 3

    Convert locally

    Your browser loads the self-hosted FFmpeg engine and processes the file locally.

  4. 4

    Download

    Save the generated file directly to your device.

Format details

Audio extraction without video output

The browser-local FFmpeg command maps the first usable audio stream, excludes video output, and encodes only that audio as MP3. An MP4 without a usable audio stream is rejected.

Helpful answers

Frequently asked questions

Is my media file uploaded?

No. Your file is written only to FFmpeg's temporary browser-local virtual filesystem and is never sent to a conversion server.

Is the video included in the MP3?

No. Video output is explicitly disabled; the result contains only converted audio.

What if the MP4 has no audio?

The conversion stops and reports that no usable audio track was found.