Rescreen / Free tools / MP4 to MP3
MP4 to MP3 converter
Drop an MP4 here and get its sound as an MP3 in seconds, at near-original quality.
Convert an MP4 file to MP3
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Drop an MP4 file here
or choose one from your device
Up to 2.0 GB. Stays on your device.
- File
- Contains
- Length
- Will become
Starting…
How to convert MP4 to MP3
Three steps, all on this page.
Choose your MP4
Choose or drop an MP4 file. The page reads what is inside and checks that this browser can convert it before anything starts.
Convert to MP3
Pick the options you want, then press Convert to MP3. Tracks that an MP3 can hold as they are get copied, which is near instant.
Check and download
The new file is opened again and checked against the original before it is offered. Listen in the preview, then download it.
What changes from MP4 to MP3
- The sound in an MP4 is usually AAC. MDN calls AAC in MP4 the standard audio pairing, supported by every major browser. Source
- AAC and MP3 are both lossy: each throws away sound it judges you will not hear. MDN warns that recompressing lossy audio compounds the loss, so use as little compression as you can. Source
- MP3 at 44.1 or 48 kHz (MPEG-1 Layer III) runs from 32 to 320 kbps. 320 kbps is the most an MP3 can use. Source
- MP4 is a container: it holds a video track, one or more sound tracks and sometimes subtitles. An MP3 file holds sound only. Source
- Browsers can play MP3 but cannot write it on their own, so this page encodes it with LAME 3.100, the long-standing open-source MP3 encoder, running inside the browser. Source
- On a Mac, QuickTime Player’s File › Export As › Audio Only saves the sound as an MPEG-4 audio file with its AAC track: an M4A, not an MP3. Source
MP4 file
MP4 (ISO base media)
- PictureH.264 or HEVC
- SoundAAC
MP3 file
MP3
- Picturenone
- SoundMP3, 128 to 320 kbps
Who converts MP4 to MP3
People who want the sound from a video they made or have the right to use: a recorded lecture to play on a walk, a talk or podcast episode filmed on a phone, a voice memo that ended up as a video, a band practice, a song of their own from a live set. Some want a smaller file to send; some need MP3 because a car stereo, an older player, a podcast host or a form only takes MP3. Only convert sound you have the right to use.
Why a long video takes seconds
An MP3 has no picture, so this page never decodes the video at all. It reads the sound track out of the MP4, decodes it and encodes it as MP3, and that is all. The picture is usually most of the file, which is why a three-minute 1080p video of about 57 MB came out as an MP3 in under three seconds on an M1 Mac, in every browser we tried.
The file never leaves your computer, so there is no upload to wait for either. A two-hour lecture is limited by your computer, not your connection.
Which bitrate to choose
The sound in your MP4 is already compressed, usually as AAC at 96 to 192 kbps. Making an MP3 means compressing it a second time, and the MP3 cannot sound better than the AAC it came from: what the first encoder threw away is gone. What the bitrate decides is how much more is lost on the way.
That is why the default is 192 kbps. For speech, music and most phone videos, it is hard to tell apart from the original. 320 kbps keeps a little more and suits music you care about; it cannot add back detail the MP4 never had. 128 kbps is fine for a lecture or a voice note you only need to follow, and it makes the smallest file.
- 128 kbps: about 0.9 MB a minute. Talks, lectures, voice notes.
- 192 kbps (default): about 1.4 MB a minute. Most things, music included.
- 320 kbps: about 2.3 MB a minute. Music you want to keep at its best.
How big the MP3 will be
An MP3 at a fixed bitrate grows by the same amount every minute, whatever is in it. The sizes above come from converting a real three-minute MP4 on this page: 2.7 MB at 128 kbps, 4.1 MB at 192 and 6.9 MB at 320, from a 57 MB video. An hour at 192 kbps is about 82 MB. If the MP3 has to fit an email, 128 kbps lets roughly 20 minutes fit under 20 MB.
If you only need an audio file, M4A loses nothing
MP3 is the right choice when something asks for MP3 by name. If you just want the sound on its own, and the player, phone or editor takes AAC (almost all do, including every iPhone, Android phone, Mac and Windows PC), extracting the AAC track into an M4A keeps it exactly as it was, with no second compression.
On a Mac, QuickTime Player does it: File › Export As › Audio Only. On any computer, ffmpeg does it in one line (below). Both copy the sound instead of re-encoding it, so the M4A is the same quality as the video’s sound and usually smaller than an MP3 at 192 kbps.
Videos with more than one sound track
Most MP4s have one sound track, but some have two or more: a second language, a director’s commentary, or a screen recording from OBS with the desktop sound and the microphone kept apart. An MP3 holds one, so when there is a choice the page lists the tracks by name and you pick which one to keep.
When not to convert
If the app or device you are sending it to plays MP4 or M4A, there is no need for an MP3: the original sound is already better than any copy of it. Converting is worth it when something insists on MP3.
Converting cannot fix the sound itself. A muffled phone recording, background hum or a quiet voice stays the same in the MP3, and choosing 320 kbps does not make a low-quality original any better; it only makes the file bigger. Keep the MP4 if you may need the video or the original sound again.
Other ways to convert MP4 to MP3
VLC Windows, Mac or Linux
- Open VLC and choose Media › Convert / Save (on a Mac: File › Convert / Stream).
- Add the MP4 and choose Convert / Save.
- For Profile, choose Audio – MP3. The spanner button next to it sets the bitrate.
- Choose a destination file ending in .mp3, then Start.
Free and offline. Check the bitrate in the profile before you start; it is easy to miss.
Audacity Windows, Mac or Linux
- Install Audacity and its optional FFmpeg library (Edit › Preferences › Libraries shows whether it is found). Without it, Audacity cannot open MP4.
- Choose File › Import › Audio and pick the MP4.
- Trim or clean up the sound if you want, then File › Export Audio, choose MP3 and a bitrate.
More steps, but you can cut, fade or reduce noise before saving. MP3 export is built in on Windows and Mac.
ffmpeg Any computer, from the command line
- Install ffmpeg (on a Mac with Homebrew:
brew install ffmpeg). - Run
ffmpeg -i input.mp4 -vn -c:a libmp3lame -b:a 192k output.mp3for an MP3 at 192 kbps. - Or run
ffmpeg -i input.mp4 -vn -c:a copy output.m4ato copy the AAC sound into an M4A with nothing lost.
The same LAME encoder this page uses, and the quickest way to convert a folder of files.
QuickTime Player Mac
- Open the MP4 in QuickTime Player.
- Choose File › Export As › Audio Only and save.
Saves an M4A with the original AAC sound, not an MP3. Ideal when M4A will do; otherwise drop the M4A or the MP4 here.
Frequently asked questions
How do I convert an MP4 to MP3 for free?
Drop the MP4 on the converter at the top of this page, choose a bitrate and press Convert to MP3. It is free, runs in your browser and nothing is uploaded. VLC, Audacity and ffmpeg are free desktop alternatives.
Does converting MP4 to MP3 lose quality?
A little, because the sound is compressed a second time. At 192 kbps or more it is hard to hear for most recordings. The MP3 can never sound better than the MP4’s own sound, so 320 kbps only helps when the original is high quality.
What bitrate should I use for MP3?
192 kbps for most things, 128 kbps for speech when a small file matters, and 320 kbps for music you care about. Going above the original’s quality only makes the file bigger.
Is it legal to convert MP4 to MP3?
Converting your own recordings, or sound you have permission to use, is fine. Converting someone else’s video or music to keep or share may break copyright and the site’s terms, depending on where you live.
Why does my MP3 have no sound?
Usually because the MP4 had no sound track, or a silent one. The page tells you before converting if there is no sound in the file. If the video has several sound tracks, check you picked the one with the voice or music.
Is my file uploaded?
No. Your MP4 is read, converted and checked on your own computer, so there is no upload and no queue. In Chrome and Edge on a computer files of any size work, written straight to a file you choose; in other browsers, files up to 2.0 GB. We count anonymous page views and whether a conversion worked; when one fails, the event also carries the step, your browser’s error and the file’s codecs, size and length in broad bands, never the file or its name. If a conversion fails you can choose to send us the file, which is deleted within 30 days. See the privacy policy.
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