Free online · No upload · Files stay on your device
MP4 to MP3 Converter
Turn MP4 video into an MP3 audio file privately in your browser. Free and no upload.
How it works
Instant conversion in 3 simple steps
Everything runs locally in your browser. Fast, zero upload wait.
01
Add your file
Drag and drop the source file. It stays in browser memory — we never upload it.
02
Confirm output
MP3 is pre-selected for MP4 audio extract. Pick WAV for lossless.
03
Download
Download your MP3 when local conversion completes.
About this converter
Convert MP4 to MP3 online without uploading. ShortVid AI reads your MP4 in the browser and encodes MP3 locally — ideal when you want the soundtrack from a clip you already have on your device.
Supported formats
Outputs we encode today. Inputs include common video and audio containers (MP4, MOV, MKV, WEBM, AVI, and more).
- MP4
- MOV
- WEBM
- AVI
- MKV
- GIF
- MP3
- WAV
Popular conversions
Why convert privately?
- No upload. Your media stays in browser memory. We do not store converter files on our servers.
- No cloud wait. Skip upload queues — conversion starts on your device with WebAssembly.
- Free & simple. No sign-up and no watermark from us on the exported file.
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Frequently asked questions
- How do I convert MP4 to MP3 for free?
- Drop your MP4 file, keep MP3 selected, and convert. Processing stays on your device.
- Is my MP4 uploaded?
- No. Conversion is private and in-browser via WebAssembly.
- Will quality be good?
- We encode a practical MP3 bitrate for sharing and playback. For archival audio, choose WAV instead.
- Does it work on phone?
- Yes on modern mobile browsers. Large MP4s convert more reliably on desktop.