How to convert MP4 to MP3
- Drop your MP4 video into the box above, or click to choose it.
- Pick an audio quality — 192 kbps (recommended) is right for most files; choose 320 kbps for music.
- Click Convert MP4 to MP3, wait for the progress bar to finish, and download your MP3.
Why extract MP3 audio from an MP4 video?
Sometimes the video is just packaging. The concert clip where you only want the song, the recorded lecture you want to listen to on your commute, the interview you need to transcribe, the podcast episode that was published as a video — in all of these, the audio is the part that matters, and the video track is dead weight.
An MP4 video carries its audio inside the file alongside the picture. This tool pulls that audio out and saves it as an MP3: the video track is discarded entirely, and only the sound is re-encoded. The result is a file that is a fraction of the size of the original video — a one-hour 1080p recording of a few gigabytes typically becomes an MP3 of well under 100 MB.
MP3 is still the most universally supported audio format there is. It plays on every phone, car stereo, smart speaker and computer made in the last twenty years, imports directly into editing tools like Audacity, and is accepted by every transcription service and audio player. If you want the audio from a video to work absolutely everywhere, MP3 is the safe answer.
The quality selector controls the MP3 bitrate. 320 kbps is the highest quality MP3 allows and is the right choice for music. 192 kbps is the recommended default — for most listeners it is indistinguishable from the source while keeping files small. 128 kbps halves the size again and is plenty for speech: lectures, meetings, voice memos and podcasts.
Your video never leaves your device
Most online MP4-to-MP3 converters work by uploading your entire video to their servers — which is slow, capped at small file sizes on free plans, and a real privacy question when the video is a family moment, a work meeting or a private interview.
SysFenix does the opposite. It runs FFmpeg — the same audio engine professionals use — compiled to WebAssembly inside your browser tab. The extraction happens on your own device: nothing is uploaded, there is no queue, no account and no server that ever sees a single frame or second of your file. Close the tab and no trace remains anywhere but your own device.
Because there is no upload, there is also no upload bottleneck: you skip transferring gigabytes of video across the internet just to get a few megabytes of audio back. The work runs at whatever speed your device can manage — modern laptops are fast, older phones take a bit longer — and the progress bar keeps you posted.
Common uses
- Saving the soundtrack or a song from a music video or concert recording.
- Turning recorded lectures, webinars and meetings into audio you can listen to on the go.
- Preparing interview audio for transcription tools that expect an audio file.
- Extracting podcast episodes that were only published in video form.
- Pulling sound effects or dialogue from clips for use in audio editing software.