Convert MP4 to MP3 online
Convert an MP4 video into an MP3 audio file without installing any software or uploading the file to a server — the whole process happens in your own browser.
or click to select it
Strips the video portion and keeps only the audio from the MP4 file, encoding it as MP3, a compressed audio format supported by virtually every player.
Use cases
- Extract the music from a video to listen to offline.
- Save the audio from a recording or interview in a lightweight format.
- Convert downloaded videos to MP3 to play on a device that doesn't support video.
How it works
- 1
Upload your MP4 video
Drop the file in or select it from your device.
- 2
Click Convert
ffmpeg.wasm extracts the audio track directly in your browser.
- 3
Download the MP3
Once it's done, download the resulting audio file.
Technical details
The audio is extracted and re-encoded as MP3 using the libmp3lame codec: this is a lossy re-encode, not an exact copy of the original audio. If you don't pick a bitrate, it defaults to variable bitrate (VBR) quality level 2; you can also pick a fixed bitrate from these specific options: 64, 96, 128, 160, 192, 256 or 320 kbps, not any value in between. A higher bitrate reduces the extra loss from re-encoding, but it can't recover detail that was already missing from the source video: the result depends on the original audio, and audio that was already low quality will still sound that way as MP3. The 300 MB per-file limit is a real, enforced limit: a larger video simply can't be started. Uses ffmpeg.wasm, a WebAssembly build of FFmpeg running inside a Web Worker in your browser; the first conversion downloads the engine (around 7 MB), and later conversions in the same session are faster since it's already loaded.
Frequently asked questions
Does converting lose quality?
The resulting MP3 uses a high encoding quality, good enough for most uses; since it's lossy compression, it isn't an exact copy of the original audio.
Is there a file size limit?
Videos up to 300 MB work reliably on most devices; larger files may exhaust the browser's available memory.