Convert MP4 to MP3
Free online converter for MP4 files. The most widely compatible lossy audio format. Nothing to install, no watermark, and every file is deleted automatically.
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Upload a MP4 file to convert it to MP3. Up to 3 files at once, 100 MB each.
Free · up to 3 files · 100 MB each · files deleted automatically after 1 hour.
About MP4 and MP3
MP4 .mp4
The universal video container, normally holding H.264 video and AAC audio. If a device plays video at all, it plays MP4.
Good for
- Plays on effectively every device, browser and editor
- Excellent compression at high quality
- Streams well, and seeks quickly
Trade-offs
- H.264 carries patent licensing obligations
- Lossy — quality drops each time it is re-encoded
- Less flexible than MKV for subtitles and multiple tracks
video/mp4
MP3 .mp3
The format that made digital music portable. Lossy, thirty years old, and still the safest choice when you have no idea what will play the file.
Good for
- Plays on essentially every device ever made
- Small files at listenable quality
- Patents long expired, so support is everywhere
Trade-offs
- Lossy — detail is gone permanently
- Beaten by AAC and Opus at the same bitrate
- No transparency about what was discarded
audio/mpeg
MP4 and MP3 side by side
| MP4 | MP3 | |
|---|---|---|
| Compression | Lossy (usually H.264) | Lossy |
| Transparency | No | n/a |
| Typically used for | Everything — the safe default for video | Music, podcasts, anything that must simply play |
What changes when you convert MP4 to MP3
Only the sound is kept
This takes the audio track out of the MP4 and writes it as MP3. The picture is discarded entirely, and no conversion back will return it — keep the MP4 if you still need the video.
This is a re-encode, not a repackage
Some tools can move a stream into a different container untouched when the codecs happen to line up. We do not — every job here is decoded and encoded again, so the conversion takes time in proportion to the length of the file and costs a small amount of quality even where a repackage would have been possible. In exchange the output is predictable: it plays everywhere, rather than inheriting whatever the source happened to contain.
What your MP3 will contain
The output is MP3 — written by LAME, the reference MP3 encoder, at 192 kbps by default. That sits comfortably above the point most people stop hearing a difference on ordinary equipment, and the bitrate is adjustable from 32 up to 320 if you want the file smaller or the quality nearer the source.
Other MP4 conversions
Other ways to get MP3
Worth reading next
MP4, MOV and MKV are not really video formats
The extension on a video file tells you far less about it than most people assume. Understanding the difference between a container and a codec explains almost every confusing thing about video conversion.
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What 192 kbps actually means, and when you need more
Bitrate is the single dial that decides how big an audio file is and how good it sounds. Here is what the numbers mean, why they are not comparable between codecs, and where the real thresholds sit.
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