MP4 to MP3 Converter

About MP4 to MP3 Converter

Last updated: October 2026

Sometimes only the sound matters - a lecture, an interview, a podcast recorded to video, a track from a clip you want on your phone. Extracting it to MP3 drops the video stream entirely, which is where almost all the size was: an hour of talk that was a 500 MB MP4 becomes a few tens of megabytes. You choose the bitrate, and the choice is worth making deliberately. 128 kbps is right for speech and keeps files small; 192 or 256 is worth it for music, where the difference is audible. The extraction runs through FFmpeg compiled to WebAssembly in your browser, so the video is never uploaded, there is no length cap and nothing is stamped on the output. One honest note: the audio in an MP4 is already compressed, so re-encoding to MP3 is a second lossy pass - inaudible for speech at any sensible bitrate, slightly costly for music.

How It Works

FFmpeg compiled to WebAssembly decodes the container, discards the video stream and encodes the audio as MP3 at your chosen bitrate. It runs entirely in your browser, with no upload and no length cap.

Use Cases

• •Turning a recorded lecture or interview into an audio file
• •Getting a podcast recorded to video onto a phone as audio
• •Extracting a soundtrack from a clip
• •Shrinking a talk recording where the picture adds nothing

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If you find MP4 to MP3 Converter useful, check out these related tools: Video to Audio Extractor, Audio Trimmer, and Audio Converter. All tools run entirely in your browser with no uploads or signups required.