Extract Audio from Video
Save the soundtrack of any video as MP3, WAV or an untouched M4A copy.
To extract audio from a video, drop the video into the Extract Audio tool, choose an Audio format of MP3, WAV or M4A, click Extract audio and download the file. M4A copies the original AAC stream with no quality loss and finishes instantly; MP3 re-encodes at your chosen bitrate; WAV gives uncompressed PCM for editing.
FFmpeg (about 30 MB) is downloaded once on first use and cached by your browser. Speed depends on your device.
How do I extract audio from a video?
- Drop your video files onto the drop zone, or click to browse. MP4, MOV, WebM, MKV and AVI are accepted.
- Choose an Audio format: MP3 (re-encode) for compatibility, WAV (uncompressed) for editing, or M4A (copy original AAC, instant) for a lossless copy.
- If you chose MP3, pick an MP3 bitrate; 192 kbps (good) is the default.
- Click Extract audio.
- Download the audio file, or Download all as ZIP when you processed several videos.
Every option starts the same way: FFmpeg opens the video, ignores the picture (-vn) and takes only the audio stream. What happens next depends on the format. M4A runs with -c:a copy, which lifts the existing AAC packets into an M4A container without decoding them; it is lossless, takes about a second regardless of length, and suits the vast majority of MP4 and MOV files because they carry AAC audio. WebM files usually carry Opus instead, so for those choose MP3 or WAV.
MP3 decodes the audio and re-encodes it with LAME at the bitrate you set. Choose it when the file has to play in something that does not handle M4A: older car stereos, some Android apps, forum attachments, podcast hosts. 128 kbps is fine for speech and 192 kbps for music; the file is about 1 MB and 1.4 MB per minute respectively. It costs a little quality compared with the M4A copy, since AAC to MP3 is lossy to lossy.
WAV decodes to 16-bit PCM with no compression at all. It is the format to pick when the audio is heading into an editor, a DAW or a transcription tool that wants raw samples, or when you need to burn a CD. The cost is size: about 10 MB per minute, so a 90 minute lecture becomes a 900 MB file. Convert to WAV, edit, then encode to MP3 or M4A for sharing.
MP3 and WAV take a few seconds per 10 minutes of audio on a laptop, since only the audio is decoded; M4A is near instant. Nothing is uploaded. FFmpeg runs as WebAssembly inside your browser, downloaded once (about 30 MB) and cached. Videos up to about 1 GB are comfortable; the browser's roughly 2 GB memory limit is the ceiling, so for a long 4K recording choose M4A, which touches the least data.
How it works: this tool uses FFmpeg compiled to WebAssembly (ffmpeg.wasm), loaded into your browser. No server is involved, so Kilnfile never sees your file. Last reviewed 20 September 2026.
Frequently asked questions
Which format should I choose?
M4A if you just want the audio as it is: it is lossless, instant and plays on phones, Macs, Windows and browsers. MP3 for the widest compatibility with older devices and web uploads. WAV if you are going to edit the audio or burn a CD.
Does extracting audio reduce quality?
Not with M4A, which copies the original AAC stream byte for byte. MP3 re-encodes and loses a little, though 192 kbps is inaudible to most people. WAV is lossless but ten times larger.
Does M4A work for every video?
It works whenever the video carries AAC audio, which covers nearly all MP4 and MOV files from phones, cameras and screen recorders. WebM files usually carry Opus or Vorbis, and some MKV and AVI files carry MP3 or AC-3; for those, choose MP3 or WAV instead.
Can I extract audio from several videos at once?
Yes. Drop them all in, choose a format and click Extract audio. Each is processed in turn and a Download all as ZIP button appears when more than one has finished.
Is the video uploaded?
No. The video is opened inside your browser by FFmpeg compiled to WebAssembly and only the audio is written out. Nothing leaves your device, and there is no signup or file limit.
Cite this page: “Extract Audio from Video Free, No Upload”, Kilnfile, https://kilnfile.com/media/extract-audio/
Related tools
Guides
- Audio formats and bitrates explainedMP3, AAC, WAV and FLAC compared with real file sizes per minute. Which bitrate you can actually hear, and when converting loses nothing at all.
- How to make a GIF from a videoTurn a clip into a GIF in your browser: pick the start, duration, frame rate and width, and keep the file under the limits for Slack, X and websites.