Video conversion
Convert MP4 to MP3
Updated Jul 2026
MP4 is a video container, and MP3 is the universal audio format. To convert MP4 to MP3, open the file in a converter and strip out the video, keeping only the audio track. Doing this on your own computer means the video, whether it's a lecture, a song, or something private, never has to be uploaded anywhere.
- Extension
- .mp4
- Type
- Video
- Typically
- The universal video format
- Compression
- Lossy
- Extension
- .mp3
- Type
- Audio
- Typically
- The universal audio format
- Compression
- Lossy
Convert MP4 to MP3 on your own computer. Nothing uploads.
How to convert MP4 to MP3
- Open Morphjet and drag in the MP4 file, or a whole folder of them, that you want the audio from.
- Choose MP3 as the output format, and pick a bitrate if you want a smaller file or higher quality.
- Convert. The MP3s are written next to your originals, and nothing leaves your machine.
MP4 vs MP3: what actually changes
| MP4 | MP3 | |
|---|---|---|
| Contains | Video and audio together | Audio only |
| File size | Much larger, video dominates the size | Much smaller, often a tenth of the MP4 or less |
| Quality | Depends on the original encode | Lossy, with a further small loss when re-encoding from the MP4's audio track |
| Plays on | Phones, computers, smart TVs, most video apps | Practically everything, including basic music players and car stereos |
| Good for | Watching | Listening, without the video weight |
| Metadata | Title, chapters, sometimes captions | Basic tags like title and artist, if you add them |
When to convert, and when not to
Convert MP4 to MP3 when you only care about the sound, like pulling a podcast, lecture, interview, or song out of a video so you can listen to it without carrying the video weight around.
Keep the MP4 if you'll ever want to watch the video again, since converting to MP3 throws away the picture for good and there's no getting it back.
Why not just use an online converter?
Video files often contain more than people realize, like a recorded lecture, a personal video call, or footage you'd rather not hand to a stranger's server just to get the audio out of it. An online converter means uploading the whole video to someone else's computer. Converting on your own machine means the video and the audio it becomes both stay put.
Questions
Does converting MP4 to MP3 lose quality?
A little. The audio in the MP4 gets re-encoded into MP3, which adds a small amount of loss on top of whatever compression the original already had. For speech and casual listening it's not noticeable, but it's not a lossless process.
Will I still have the video after converting?
No. Converting to MP3 keeps only the audio track and discards the video entirely. Keep a copy of the original MP4 if you might want the picture later.
Does the MP3 keep the title or other info from the video?
Basic tags like a title can usually carry over or be added, but chapter markers, captions, and other video-specific metadata don't survive the conversion since MP3 has no place to put them.
Can I pull audio from a video without uploading it anywhere?
Yes. A desktop app like Morphjet reads the file and writes the MP3 locally, so the video never has to leave your computer or touch the internet.
Why is the MP3 so much smaller than the MP4?
Because video takes up the vast majority of an MP4's size. Once that's stripped away and only the compressed audio remains, the file shrinks dramatically, often to a fraction of the original.
Morphjet converts MP4, MP3, and 1,800+ other formats, all on your machine. Launching this July.