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Asset Compressor

Convert MP4 to MP3

Turn MP4 videos into MP3 audio you can play in the car, on any phone or in a podcast app. Conversion takes seconds and happens entirely on your device.

  • No upload
  • No watermark
  • No file size limit
  • Hardware accelerated

Drop videos here to convert them

MP4, MOV, WebM, MKV, AVI and more · no size limit or watermark

Processed on your device. Your videos are never uploaded.

Output format

Saves only the soundtrack as an MP3 file.

Advanced: codec, frame rate, audio, trim
Audio
Trim

Use m:ss or seconds. Applies to every video in the list.

How to convert an MP4 to MP3

  1. 1

    Select your MP4 files

    Drop in one MP4 or a batch – recordings, lectures, interviews or music videos you own.

  2. 2

    Keep 192 kbps or lower it

    192 kbps is ideal for music. For speech, 128 kbps sounds the same and makes smaller files.

  3. 3

    Convert

    MP4 files are read by your browser directly, so only the audio has to be encoded – it is quick even for long videos.

  4. 4

    Download your MP3s

    Download each MP3, or get them all in one ZIP.

What happens when you convert MP4 to MP3

An MP4 file usually holds H.264 video and AAC audio. To make an MP3, Asset Compressor reads the audio track, decodes it and encodes it again with an MP3 encoder at the bitrate you choose. The video track is skipped entirely, which is why the conversion is fast and the result is tiny compared with the video.

Because the AAC audio is re-encoded, choose a bitrate at least as high as you need: 192 kbps keeps music transparent for most listeners, 128 kbps is plenty for voices.

MP3 or keep AAC?

MP3 is the most compatible audio format there is: car stereos, old MP3 players, smart speakers, editing apps and every phone play it. AAC (M4A) is slightly more efficient, but some devices and upload forms only accept MP3. If you are not sure, MP3 is the safe choice.

Typical uses

Students convert recorded lectures to listen on the way to class. Podcasters pull the audio from a video interview to edit it. Musicians extract a rehearsal or performance from a phone recording. In each case trimming helps: set a start and end time under Advanced to keep just the part you need.

A one-hour recording at 128 kbps is about 55 MB – small enough to send in most messaging apps.

Other video formats

Have MOV, MKV, WebM or AVI files instead? They convert the same way – see the video to MP3 converter for all formats.

Frequently asked questions

Does MP4 to MP3 conversion lose quality?

Very little at 192 kbps. The MP3 can never sound better than the MP4’s original audio, so choosing a higher bitrate than the source only makes the file larger.

How long does it take?

Usually seconds to a minute, because only the audio is processed and MP4 files are read natively by your browser.

Can I convert a YouTube video to MP3?

No. Asset Compressor doesn’t download from websites – it converts files that are already on your device. Only convert content you have the rights to.

Can I convert several MP4s at once?

Yes. Add as many files as you like; they are converted one after another and can be downloaded as a ZIP.

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