MP4 to MP3
AvailableExtract the audio track from an MP4, M4V or MOV file and download it as MP3. Uses FFmpeg compiled to WebAssembly, so the file never leaves your browser.
MP4 to MP3
Available
Or paste a direct video link
MP4 · M4V · MOV
Works with a direct .mp4, .m4v or .mov file whose
server allows this page to read it (for example your own site, a CDN or an S3 bucket).
YouTube, Instagram, TikTok, Facebook and Vimeo page links cannot be read by a
browser — download the video from those sites first, then drop the file
above.
Nothing to show yet
—
Only the audio track is encoded; the video frames are discarded.
Output
Always writes an .mp3 file
Validated locally: file type, size and browser support are checked before anything runs
Preparing your file
Reading the file locally and checking that its type and size match what this tool expects. Nothing has been uploaded.
Converting locally
FFmpeg runs in a Web Worker, so the page stays responsive while the audio is extracted.
- Read
- Validate
- Convert
- Package
You can leave this tab open in the background — the conversion keeps running on your device, and progress is reported when you come back.
Conversion complete
Your converted file is ready to download.
Nothing to show yet
—
Nothing to show yet
—
Output format
MP3
Duration
—
Processed
On your device
Size change
—
The converted file was assembled in your browser and is released when you leave or reset this page
Something went wrong
The conversion could not be completed. Nothing was uploaded, and no partial file was saved.
This conversion is not supported yet
Your file passed every local check, and this is exactly where the FFmpeg (WebAssembly) engine takes over. It does not implement this particular input and output pair yet, so nothing was converted and no download was offered.
| Engine | FFmpeg (WebAssembly) |
|---|---|
| Frontend module | static/engines/media-engine.js |
| Extra downloads | About 31 MB of FFmpeg WebAssembly, loaded on the first run and cached afterwards |
| Runs in a worker | Yes — FFmpeg runs in its own Web Worker |
| Processing | On your device |
This page is the integration point. When the engine lands, it is loaded here and the same six states drive the real conversion.
No upload for supported tools — the file is processed by this browser
Up to 50 MB
About this converter
Extract the audio track from an MP4, M4V or MOV file and download it as MP3. Uses FFmpeg compiled to WebAssembly, so the file never leaves your browser.
What happens to your file
For supported tools the file is read with the browser File API and held in memory on your device. It is validated, processed by the FFmpeg WebAssembly engine in a Web Worker, and the result is handed back as a download. At no point is the file sent to a server.
What to expect from the output
The tool writes MP3. Formats differ in what they can represent, so expect the audio to be re-encoded to MP3, while the video track is discarded.
How to use this converter
Four steps, none of which involve an account.
-
1 Choose your file
Drop an mp4, m4v or mov file onto the drop area or browse for it.
-
2 Check the output
The output is always MP3. Adjust the audio quality if you need a smaller file.
-
3 Convert
Everything happens on your device, so speed depends on your machine rather than a queue.
-
4 Download
Save the result, then reset the tool to clear it from memory and start again.
Conversion states
Design referenceThese are the six states the workspace moves through. The live tool above uses the same markup; this panel shows each one side by side so the behaviour can be reviewed without converting anything.
1 Empty — no file chosen
2 File selected — ready to convert
- MP4 clip.mp4
3 Preparing — reading locally
Preparing your file
Checking the file type and size. Nothing has been uploaded.
4 Converting — progress reported
Converting locally
- Read
- Validate
- Convert
- Package
Runs in a Web Worker so the page stays responsive.
5 Completed — result ready
Conversion complete
Your converted file is ready to download.
# Release notes
- Faster audio extraction
- **New:** Markdown to PDF
- Fixed line ending detection
release-notes.md
Release notes
Faster audio extraction
New: Markdown to PDF
Fixed line ending detection
release-notes.html
Output format
MP3
Duration
—
Processed
On your device
Size change
—
Interface preview
This is the completed state as designed. No file was converted and the download action is disabled, because the conversion engine for this tool has not been connected yet.
The converted file was assembled in your browser and is released when you leave or reset this page
6 Error — recoverable
That file could not be read
The file appears to be damaged or its contents do not match the
.mp4 extension. Nothing was uploaded.
Try again
Choose a different file
Frequently asked questions
Answers specific to MP4 to MP3.
Is this tool free?
Yes. MP4 to MP3 is free to use and needs no account, no sign-up and no email address.
Where is my file processed?
Entirely in your browser. The video is read into memory and FFmpeg, compiled to WebAssembly, extracts the audio track. Nothing is uploaded to a server.
Which files can I use as input?
Accepted formats are MP4, M4V and MOV video files. The converter writes MP3 audio.
Does converting to MP3 reduce the video quality?
The video is discarded, so there is no video quality to keep. Only the audio track is re-encoded to MP3 at the quality you choose.
Why does the first conversion take longer?
The first run downloads and starts the FFmpeg WebAssembly engine (about 31 MB). The browser caches it, so later runs start much faster.
Can I paste a YouTube or Instagram link?
No. YouTube, Instagram, TikTok, Facebook and Vimeo links open a web page, not a video file, so a browser cannot download them without a server-side extractor — and this tool has no server. A direct .mp4, .m4v or .mov link does work when its server allows the page to read it, for example your own website, a CDN or an S3 bucket.