MP4 to MP3 Converter - Extract Audio, Free
Pull the audio track out of an MP4 video and save it as an MP3, entirely in your browser. Trim to just the section you need before extracting, or keep the whole thing.
Maintained by Hirantha Sandaruwan Lakshan. Updated 31 July 2026.
How it works
The video's audio track is read directly and re-encoded to MP3 through a real LAME encoder running as WebAssembly - the video track itself is discarded rather than decoded, which is what keeps this fast.
The tool never fully decodes the video to extract audio - it streams through the file's encoded packets directly, which keeps memory use low even for a long recording.
Set an in-point and out-point before extracting if you only need a section, like the music from part of a longer video.
Worked examples
Pulling a song out of a music video
Drop in the MP4, trim to the section you want, and download just the MP3 audio.
Getting the audio from a recorded lecture or meeting
Extract the full audio track as MP3 for a smaller file that's easier to share or listen to on the go.
Creating an audio version of a podcast video
Convert a video podcast episode to MP3 for audio-only distribution.
Frequently asked questions
Is my video uploaded anywhere?
No, the whole process runs in your browser tab.
Can I trim before extracting the audio?
Yes, set an in and out point and only that section is extracted.
Does it keep the video quality info or just audio?
Only audio - the output is a standard MP3 file with no video track.
Is there a file size limit?
There's a soft warning on very large files on mobile, but no hard cap - it depends on your device's memory.
What bitrate is the extracted MP3?
The audio is re-encoded at a bitrate chosen to stay transparent for speech and music without inflating the file. For most source videos the result is indistinguishable from the original track.
What if the video has no sound?
There's nothing to extract, and the tool says so rather than handing you a silent file.
Does this work with MOV, MKV, or WebM too?
Yes. Any video your browser can decode works the same way, not just MP4.
Why does a long video take a while?
The audio track still has to be decoded and re-encoded end to end. It's much faster than re-encoding video, but it isn't instant on a feature-length file.
Does this work on my phone?
Yes - it runs in your phone's browser with no app to install. A very long video is more likely to run into memory limits on a phone than on a laptop.
Sources & references
Updated Jul 31, 2026