MP4 to MP3 converter
Convert MP4 to MP3 in your browser, with nothing uploaded.
Processed in your browser. This file is converted on your device and is never uploaded.
Converter
.mp4 up to 250 MB. You can also drag a file here.
No file selected.
About this tool
This page converts MP4 to MP3 in your browser. The file is read from your own device, decoded and re-encoded by code running on it, and handed back as a download. It is never uploaded, because there is no conversion server here to upload it to.
A MP4 file holds a picture and a soundtrack side by side. Converting one to MP3 means keeping the sound and discarding the video entirely, which is why the result is a small fraction of the size you started with.
MP4 is a container, not an audio format. It holds a video stream and an audio stream together, and it is what a phone camera, a screen recording, and almost every download produces.
The audio inside a video is often the only part worth keeping — a talk, an interview, a piece of music with a static image over it. Extracting it turns a file too big to carry into one that plays with the screen off and takes almost no room.
Nothing else plays in as many places. An MP3 works on hardware old enough to predate streaming and on anything sold since, which is why it remains the answer whenever the question is whether the file will open at all.
Audio conversion needs a real codec, so the first conversion in a session downloads FFmpeg compiled to WebAssembly — a few megabytes, fetched once and then reused. It is the same file for every visitor and it arrives before you have chosen anything, so it says nothing about your recording. Everything after that happens on your device.
Supported formats and limits
- Input
- .mp4
- Output
- .mp3 (audio/mpeg)
- Output name
- The original name with the new extension, for example track.mp4 becomes track.mp3.
- File size limit
- 250 MB
- Processing
- In your browser. The file is not uploaded.
MP4 against MP3
| Feature | MP4 | MP3 |
|---|---|---|
| Compression | Lossy — detail is discarded permanently | Lossy — detail is discarded permanently |
| Three minutes, stereo | About 3–6 MB | About 3–7 MB |
| Artist and album tags | Yes | Yes |
| Plays in browsers | Yes | Yes |
| Introduced | 2001 | 1993 |
| Quality setting | You choose it | You choose it |
When you would want this
Keeping the talk and not the slides
A recorded lecture, interview, or conference talk is usually worth listening to and not worth watching. Dropping the video leaves a file small enough to keep on a phone and to play with the screen off, which a video will not do.
Playing it on something that will not read the original
Car stereos, gym equipment, older iPods, and cheap MP3 players each read a short list of formats and reject everything else without explaining why. Converting to a format on that list is usually the whole fix, and it is why MP3 is asked for far more often than it is chosen on merit.
Publishing speech
Podcast hosts and submission forms almost always want MP3, often with a size limit attached. Speech survives heavy compression far better than music does, so the lowest quality setting is frequently the right one here.
How to use it
- Choose a MP4 file, or drag one onto the box.
- Pick a quality. Higher sounds better and produces a larger file; the middle setting is what most people want.
- Select convert and wait. The first run also loads the audio engine, so it takes longer than the ones after it.
- Download the result. Nothing is kept: leaving or resetting the page releases it.
Limitations
- The video is discarded. What you get is the soundtrack alone, with no way to put the picture back.
- Both MP4 and MP3 are lossy, so this conversion compresses an already-compressed recording. The result is slightly worse than the input no matter which quality you pick, and converting back and forth repeatedly makes it audibly worse.
- The output is usually larger than the input — roughly 3 to 7 megabytes for three minutes of stereo. That is expected and is not a sign anything went wrong.
- The audio inside an MP4 is already lossy, usually AAC, so it has been compressed once before you begin.
- An MP4 can hold several audio tracks; the first one is the one that comes out.
- The audio engine is a few megabytes and is downloaded the first time you convert something in a session. On a slow connection that wait is real, and it happens before the conversion starts rather than during it.
- One file at a time. Audio conversion is heavy enough that running several at once is a good way to exhaust a phone's memory.
- A long recording takes a long time. Converting an hour of audio runs for minutes rather than seconds, and the tab has to stay open while it does.
Common problems
I wanted the video too, and the result has no picture.
This tool extracts the soundtrack. The video stream is dropped deliberately, and the output format could not carry it anyway.
Keep the original file if you want the video. This conversion is for when the sound is the part you need.
The result is larger than the file I started with.
The output format stores more per second than the input did. That is what it is for, and it is not an error.
If size matters more than fidelity, use a lossy format such as MP3 or OGG instead, or lower the quality setting.
The result sounds duller or thinner than the original.
A lossy encoder was run over audio a lossy encoder had already been run over, and each pass removes something.
Convert from the least-processed copy you have rather than from an export of an export, and choose the highest quality setting.
The converted file plays but there is no sound.
The source had no audio track, or the track it had was one your browser could not decode.
Play the original first and confirm you can hear it. A screen recording made without audio permission produces exactly this: a valid file with a silent track.
The MP4 has more than one language track and the wrong one came out.
Only the first audio stream is extracted. A file with several will silently give you whichever one the container lists first.
Use a player or a desktop tool that lets you choose the stream. This page has no way to show you a list, because it would have to decode the file before you had asked it to do anything.
It is taking far longer than expected.
The first conversion of a session downloads the audio engine, and long recordings take proportionally long to process.
Leave the tab open and in the foreground. A background tab is throttled by the browser and will crawl.
Other ways to do this
A desktop player that can save the audio
VLC and similar players extract a soundtrack from a video without re-encoding it at all, keeping the original audio stream exactly as it is. That is the better result when the format inside the MP4 is already one you can use.
A desktop audio application
Audacity, foobar2000, and similar programs convert audio and do a great deal else besides. They are the better choice for batches of hundreds of files or for work that needs editing as well as conversion. They are a download and an installation, which is the trade.
FFmpeg on your own machine
This page runs FFmpeg compiled to WebAssembly. The native command-line version does the same conversion faster, handles thousands of files in a loop, and exposes every option there is. If you already have it installed, use it.
Not converting at all
Check first whether the thing you are trying to play actually refuses the format. Modern phones, browsers, and media software read far more than they did a decade ago, and a conversion you do not need costs quality for nothing.
Frequently asked questions
- Does converting to MP3 lose quality?
- It depends on the format you are converting to, and this page says which case it is in the limitations above. A lossless output stores what it is given exactly; a lossy one discards detail to be smaller. Neither can recover anything the source had already lost.
- Which quality setting should I choose?
- The middle one, unless you have a reason. It is indistinguishable from the original for most listeners on most equipment. Choose the highest if the file is going into a library you intend to keep, and the lowest for speech, which survives compression far better than music.
- Can I get the video back afterwards?
- No. The output holds sound and nothing else, and the picture is not stored anywhere in it. Keep your original file if you may want the video later.
- Are the artist and album kept?
- Where the output format has somewhere to put them, yes. WAV does not, so those pages say so plainly. Cover art is more fragile than text tags and is the first thing to be dropped.
- Is there a limit on how long the recording can be?
- The limit is on file size rather than duration, and it is stated above. In practice a long recording is limited by patience and by memory: everything happens on your device, so an hour-long file will take minutes and will use real memory while it does.
- Can I convert back the other way?
- The file will convert back, but quality does not return with it. Anything a lossy encoder discarded is not in the file to be recovered, so a round trip leaves you with something worse than where you started rather than back where you began.
- Does the video quality matter for the audio I get?
- No. The soundtrack is stored separately from the picture inside the container, so a heavily compressed video can carry perfectly good audio and a pristine one can carry poor audio. What matters is the bitrate of the audio stream, not of the video.
- Is the result the same as what a desktop program would produce?
- Yes. This is FFmpeg, the same software most desktop converters use underneath, compiled to run in the browser. The encoders are identical, so the output is too. What differs is speed, because a browser sandbox is slower than native code.
- Do I need to install anything or create an account to use MP4 to MP3 converter?
- No, to all of it. MP4 to MP3 converter runs inside the browser you already have, with no sign-up, no download, no watermark on the result, and no cap on how many files you convert. There is nothing to uninstall afterwards either, because nothing was installed.
- Does MP4 to MP3 converter work offline?
- After the first conversion, yes. Audio work needs the FFmpeg engine, which is a separate download of a few tens of megabytes fetched the first time you convert something. Once your browser has cached it the work is entirely local and a connection is no longer needed.
- How large a file can MP4 to MP3 converter handle?
- The limit is 250 MB. It is a deliberate one rather than a technical ceiling: the real constraint is memory, and a file that decodes to more than the device can hold fails in a way that is hard to explain. Phones run out well before laptops do, which is why the limit is set where it is.
- Can I convert several files at once with MP4 to MP3 converter?
- Not here: this tool takes one file at a time, because what it does depends on choices you make about that particular file. Convert them one after another, or look at the batch converters in the same category, which are built for a folder at a time.