MP4 to MP3 Converter
Runs in your browser — your files are never uploaded.
Extract the audio track from an MP4 video and save it as an MP3. Useful for lifting the sound out of a phone recording, a screen capture, a lecture or an interview so you can listen without the video. OkConverter runs a real copy of ffmpeg compiled to WebAssembly right in your browser tab, so even a long recording never leaves your device — and there is no length cap or watermark.
How to convert MP4 to MP3
- 1
Drop your .mp4 file onto the box, or click to choose one.
- 2
OkConverter loads the conversion engine (one-time per session) and extracts the audio locally.
- 3
Click “Download” to save the MP3.
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Frequently asked questions
What quality is the MP3?+
Variable bitrate at roughly 190kbps, which is near-transparent — you would struggle to tell it from the audio inside the original MP4. Bear in mind the video’s own audio track is already compressed, so this cannot be better than the source.
How is this different from the Video to MP3 tool?+
Only the label. That page accepts MOV, MKV, WebM and AVI as well; this one is aimed at the MP4 files most people actually have. The extraction is identical.
Is there a file size or length limit?+
There is a 500MB input cap to stop a runaway file hanging your tab, but no server-side limit — a full-length lecture or podcast recording is fine.
The download is empty or fails — why?+
Almost always because the MP4 has no audio track at all, which is common with screen recordings made without microphone permission. Check the video plays with sound first.
Is my video uploaded anywhere?+
No. The engine downloads once, but your video is read and decoded entirely inside your browser tab. The file itself never leaves your device.