Convert MP4 to MP3 Online

Upload an MP4 video file and extract the audio as a high-quality MP3. Fast, free, and works entirely in your browser.

How it works

  1. Upload your MP4 video. Drag your MP4 file into DomeScribe or click to browse. The tool accepts MP4 files of any length, from short clips to full-length movies.
  2. Preview the audio track. DomeScribe detects the audio stream embedded in your MP4 container and displays its properties, including codec, sample rate, and channel layout.
  3. Set MP3 quality and bitrate. Choose your preferred MP3 bitrate — 128 kbps for smaller files, 192 kbps for balanced quality, or 320 kbps for near-CD fidelity. You can also adjust the sample rate if needed.
  4. Extract audio and download. Click Convert to strip the video layer and encode the audio as MP3. The resulting file is ready for music players, podcasts, or any device that supports MP3 playback.

Converter at a glance

Video formats
MP4, WebM, MOV, AVI, MKV
Audio formats
MP3, WAV, FLAC, M4A, OGG, AAC
Privacy
Runs 100% in your browser (WebAssembly) — your file is never uploaded to a server
Speed
No upload or download wait — conversion starts instantly, even for large files
Watermark
None, ever
Free tier
10 conversions per month

Frequently asked questions

Does converting MP4 to MP3 affect audio quality?

The audio quality depends on the bitrate you choose in DomeScribe and the quality of the original audio track inside the MP4. If the source video has high-quality AAC audio at 256 kbps, converting to MP3 at 320 kbps will produce excellent results with no perceptible difference for most listeners.

How much smaller will the MP3 be compared to the MP4?

Dramatically smaller, because the video data — which accounts for the vast majority of an MP4 file — is discarded entirely. A 500 MB music video run through DomeScribe typically produces an MP3 file under 10 MB, depending on song length and chosen bitrate.

Can I extract audio from a long MP4 recording like a lecture or podcast?

Yes, DomeScribe handles MP4 files of any duration. Long recordings such as lectures, webinars, or podcast episodes convert smoothly, and the resulting MP3 is ideal for offline listening on phones or portable players.

What bitrate should I choose when converting MP4 to MP3?

For music, 256 kbps or 320 kbps provides near-transparent quality. For spoken word content like audiobooks or interviews, 128 kbps is sufficient and keeps file sizes minimal. DomeScribe defaults to 192 kbps as a balanced starting point.

Will metadata like the song title transfer to the MP3?

DomeScribe carries over common metadata fields such as title, artist, album, and track number from the MP4 container to the MP3 ID3 tags whenever they are present in the source file. You can also edit tags after conversion.

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