Konvizi
Free No upload
Drop your MP4 files: their sound is converted to MP3 on your device, without uploading anything.
Drop your MP4 files here
or
Your files stay on your device
Konvizi’s “MP4 to MP3” tool is free, with no sign-up, no watermark and no file limit. All the processing happens in your browser, on your device: your files are never uploaded to a server, which makes it suitable for personal and confidential documents.
Drag your MP4 files into the box above or click “Choose files”. You can add several at once.
Your browser reads the sound of each file and saves it as MP3. Nothing is sent over the internet.
Get your MP3 files one by one, or all together with “Download all”.
MP4 is the most common video format: phone videos, downloads and most websites use it. It holds a video track and, usually, an audio track.
To keep only the sound of a video (music, an interview, a lecture), there is no need to keep the picture: an MP3 file is much lighter and plays everywhere.
MP3 is the most widespread audio format. It compresses sound by removing what the ear barely hears, giving files about ten times smaller than a raw recording.
An MP3 plays absolutely everywhere: phone, computer, car, speaker, website. Konvizi saves it at 192 kbps, very close to the original for both music and voice.
Voice memos, meeting recordings, music: the sound is decoded and re-encoded by your browser, with no upload. No waiting while a big file uploads, and no private recording ends up on a server.
Your files never leave your device. No upload, no storage.
No upload and no queue: the conversion starts right away.
As many files as you like, with no imposed size limit.
No sign-up, no watermark, no subscription.
| Konvizi | Typical online converter | |
|---|---|---|
| Where your files are processed | In your browser, on your device | On the service’s servers |
| Upload to the internet | None | Required, then you download the result |
| Storage of your files | None: nothing is stored | Stored on a server, at least while processing |
| Waiting time | Starts instantly | Upload time, sometimes a queue |
| Account | Never required | Often required beyond a few files |
| Watermark and limits | No watermark, no maximum number | Common on free plans |
Yes, completely. No sign-up, no watermark, no maximum number of files: you can convert as many files as you like.
No. Everything happens in your browser, on your device. Your files are never sent over the internet: nobody but you can see them.
MP3s are encoded at 192 kbps (128 kbps for mono sound), 44.1 kHz: very close to the original for both music and voice. One minute of stereo sound is about 1.4 MB.
Yes, but the whole video is read by your device: for a film over an hour long, a computer does better than a phone. MOV and M4V files are accepted too. If the video has no audio track, Konvizi tells you.
Open your browser’s developer tools (F12 key), go to the “Network” tab and run a conversion: no request carries your file. The site also enforces a security rule (Content-Security-Policy) that forbids the browser from contacting any site other than konvizi.com, and konvizi.com is a static site with no service able to receive files.
Yes. Konvizi works in the browser of your phone or tablet (Safari, Chrome…) just like on a computer, with no app to install. Very large files are processed faster on a computer, which has more memory.