Free video/audio converter
MP4 to MP3 Converter
Extract the audio track of an MP4 video and save it as an MP3, directly in your browser. The conversion runs on a WebAssembly build of FFmpeg loaded on demand — nothing is uploaded to a server.
Convert MP4 to MP3
Drop an MP4 video here, or click to choose a file
Processed locally in your browser — nothing is uploaded.
100% local — your file never leaves your device. The first conversion downloads a ~30MB FFmpeg engine to your browser; later conversions are fast.
Frequently asked questions
Is this MP4 to MP3 converter really free?
Yes, entirely free, with no account, watermark, or file limit imposed by a server — because there is no server involved.
Does my video get uploaded anywhere?
No. The video is processed locally in your browser using a WebAssembly build of FFmpeg. It never leaves your device.
Why does the first conversion take longer?
Your browser downloads the FFmpeg WebAssembly engine (roughly 30MB) the first time you use this converter. It's cached for the rest of your session.
Will this work for large video files?
It depends on your device's memory, since everything runs in your browser tab rather than on a server. Very large files (multiple GB) may be slow or run out of memory on lower-powered devices.
Doing this by hand every week? That's exactly what I remove.
If this conversion is one small step in a bigger workflow — say, files arriving by email, getting converted, renamed and filed by a person every time — I build software that does the whole thing automatically. My clients get back up to 18 hours a week this way.
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