MP4 to MP3
Choose a video or audio file and download its sound as an MP3. The file is decoded and encoded on your device, so nothing is uploaded.
Choose an audio or video file.
About this tool
Your browser already decodes MP4 audio to play it back; this tool reuses that decoder and re-encodes the samples as MP3 with LAME compiled to WebAssembly. There is no server, so there is no queue, no upload wait and no file retention policy to trust.
192 kbps is a good default for speech and most music; 320 kbps is close to transparent for anything you would notice; 128 kbps keeps podcasts small. The video track is simply ignored, so a 500 MB screen recording becomes a few megabytes of audio.
Frequently asked questions
- Is there a file size limit?
- Only your device's memory. The whole file is decoded in RAM, so very long recordings on a phone may fail where a laptop succeeds.
- Which input formats work?
- Anything your browser can play: MP4, M4A, MOV, MP3, WAV, OGG, WebM and usually FLAC.
- Does the quality drop?
- MP3 is lossy, so re-encoding always loses a little. Pick 256 or 320 kbps if the source is already high quality.