01
Add your MP4
Drop an MP4 video (or audio-in-MP4) on the panel, choose it from disk, or open it from Your Library. Common phone and camera MP4 files are accepted when the browser can decode them.
MP4 to MP3
Extract audio from an MP4 video into MP3 for music apps, podcasts, and sharing — right in your browser.
Drop an MP4 file here
or click to choose from your computer
MP4 · M4V · H.264 · common phone/camera exports
Your file will be converted to MP3 (audio). Click Convert when ready.
Converting…
Local processing in your browser · Files are not uploaded to our servers
About MP4 to MP3 conversion
MP4 files from phones, cameras, and screen recordings often include both picture and sound. MP4 to MP3 keeps only the soundtrack as a compact MP3 you can play on phones, in music apps, or in audio editors.
Sound Booster extracts audio in the browser: add an MP4, convert to MP3, then download or save to Your Library. Everyday files are meant to stay on your device for this step rather than being uploaded to a remote server.
Use this when you recorded a meeting, lesson, or tutorial as video but only need the voice track, or when a form accepts MP3 and not MP4. Support teams and creators often strip audio from a screen capture before attaching a small file to a ticket or chat.
Silent MP4 files will not produce useful audio — check that the recording included a microphone or system sound. Progress is shown as a percentage while encoding runs. Very long clips need enough memory; if conversion fails, try a shorter segment first.
How to convert MP4 to MP3
Converting MP4 to MP3 on Sound Booster is a short, local process: you add the video, extract the soundtrack, and download an MP3 without installing desktop software. Keep this tab open until progress reaches 100% so encoding can finish.
The page is fixed to MP3 output, so you do not need to pick a format from a long list. If the MP4 is very long or high resolution, the first run may take longer while the browser converter engine loads; shorter clips are usually faster.
02
Convert to MP3
Click Convert to MP3. The picture track is discarded; only the soundtrack is encoded as MP3. Progress shows as a percentage while the engine works in your browser.
03
Download or save
Save the MP3 to your device, or store it in Your Library so you can open Volume Booster, Trimmer, or other audio tools without re-uploading the file.
MP4 and MP3 formats
What is an MP4 file?
MP4 is a web media container. Browser recordings often include both picture and sound. When you only need the voice or music track, extracting audio to MP3 is faster than keeping a full video file.
What is an MP3 file?
MP3 is a widely supported compressed audio format. It is small enough for sharing and accepted by most phones, cars, and podcast tools. Quality depends on bitrate; this tool targets a practical balance for speech and general listening.
What people use it for
Voice from screen recordings
Keep the narration from an MP4 capture without the video track — ideal for meetings and tutorials where the picture is secondary.
Podcasts and voice notes
Turn a browser recording into an MP3 ready for players, podcast tools, and simple audio editors.
Smaller files for sharing
Send audio instead of a full MP4 when the picture is not needed and inbox size limits matter.
Audio tools next
Save MP3 to Your Library and open Volume Booster, Trimmer, or other Sound Booster tools without re-uploading.
Frequently asked questions
Is video removed?
Yes. MP4 to MP3 exports audio only; the picture is not kept in the MP3 file.
Do my files leave this device?
No. Conversion is designed to run in the browser.
What if the MP4 has no sound?
You will not get a useful MP3. Check that the recording included a microphone or system audio.
Is it free?
Yes on this page, without a mandatory account.
Why did conversion fail?
Try Chrome or Edge, a shorter file, and keep the tab open until progress reaches 100%.