Free browser tool
Free MP4 to MP3 Converter
Extract audio from MP4 (and similar video) to MP3 locally with ffmpeg.wasm.
Note: ffmpeg.wasm is tens of MB. Long videos are slow — short clips work best.
Drop a video here
MP4 / MOV / WebM — conversion runs on your device
100% client-side via ffmpeg.wasm. Your video never leaves this device.
About this MP4 to MP3 converter
Upload a video file and extract an MP3 soundtrack entirely in the browser using ffmpeg.wasm.
The WASM payload is tens of megabytes and long videos are slow — prefer short clips for a smoother experience.
When you need agent workflows beyond file conversion, try okayok.ai.
Why convert here
Client-side ffmpeg
Uses ffmpeg.wasm so audio extraction never requires a server upload.
Private by design
Your video stays on device during conversion.
Short clips recommended
WASM download and encode time grow with file length.
Related video tools
Pair with Video Scene Cuts for shot detection.
How to convert
- 1
Choose a video
Drop an MP4, MOV, or WebM file.
- 2
Wait for ffmpeg
The first run downloads the WASM core (tens of MB).
- 3
Download MP3
Preview and save the extracted audio.
FAQ
More video tools
Compress Video
Shrink video toward a target file size with bitrate or CRF.
Trim Video
Cut a clip by start and end time with accurate seek.
Resize Video
Scale to 1080p, 720p, 480p, or a custom width.
Video Watermark
Add text or image watermarks with corner/center positions.
Video Speed
Speed up or slow down 0.5x–2x with setpts + atempo.
Video to GIF
Turn a short clip into a GIF with fps/scale limits.
More from Okay OK
Okay OK is the official home of the OK product family — OK Tools, OK Video, OK Images, and more.
Visit okayok.ai