Convert MKV to MP3
To convert MKV to MP3, drop the Matroska file into the converter on this page and click the button; the audio is extracted and downloaded as an MP3 while the video is dropped. The whole job runs through ffmpeg in your browser, so a large movie file is never uploaded anywhere.
Runs in your browser. Your file never leaves your device.Drop your MKV hereChoose a MKV to convert
It becomes a MP3 right in your browser, up to 200 MB
Your file never leaves your device
Works in airplane mode. See the proof
Limits, published exactly
| Where it runs | In your browser. The file never leaves your device. |
|---|---|
| Free conversions | Unlimited. No account, no ads, no queue, no watermark. |
| Max file size, free | 200 MB |
Why convert MKV to MP3?
MKV is the format of serious video collections: movies, anime, concert footage and high-quality rips live in it because the Matroska container can carry several video, audio and subtitle tracks in one file. Sometimes you only want the sound, the score from a film, the dialogue from an episode for study, a commentary track to listen to on the move, and you do not want to drag a multi-gigabyte video around to get it. Extracting to MP3 gives you a compact audio file that plays on any phone or player. It is also the easiest way to feed a transcription or editing tool that has no idea what to do with a Matroska container.
What is MKV?
MKV is the Matroska container: an open, anything-goes wrapper that can hold any video codec along with unlimited audio tracks, subtitles and chapters. That flexibility makes it the favorite of screen recorders, rippers and archivists, and also the reason TVs, phones and editing tools reject it so often. Converting to MP4 trades the extras for a file that plays essentially everywhere.
What is MP3?
MP3 is the audio format that ate the world in the late 1990s, and it remains the most universally supported way to store sound: lossy compression at roughly a tenth of CD size, playable on literally anything with a speaker. Newer codecs like AAC and Opus beat it on quality per kilobyte, but no format comes close to its compatibility across car stereos, ancient MP3 players, browsers, editing software and upload forms.
Quality and what to expect
The audio inside an MKV can be anything from AAC to AC-3 to FLAC, and it is re-encoded once to MP3 by LAME at a high variable bitrate (around 190kbps equivalent); the video stream is discarded rather than converted, so this runs quickly even on big files. Honest caveat worth knowing: MKV files often hold multiple audio tracks, and this extraction takes the default or first one, so if the language or commentary you wanted is on a later track, the MP3 may not contain it. If the source audio was itself lossy, you are adding a small second generation of loss; if it was lossless, this is the one lossy step.
MKV to MP3 FAQ
Which audio track do I get if the MKV has several?
The default or first audio track in the file. Matroska files commonly bundle multiple languages and a commentary track, and this conversion does not let you pick among them, so if you need a specific one, it may not be the one extracted.
Is my movie file uploaded to pull the audio out?
No. The MKV is handed to the ffmpeg WebAssembly engine inside your browser, the chosen audio track is re-encoded locally, and the video is discarded on your machine. The file never crosses the network.
Does extracting audio re-encode the whole video?
No, and that is why it is fast. The video stream is thrown away untouched; only the audio track is decoded and re-encoded to MP3, so even a feature-length MKV processes far quicker than a full transcode would.
Will the MP3 quality match the original audio track?
Close. The track is re-encoded once to MP3 at a high bitrate. If it was already lossy (AAC, AC-3) you add a small generation of loss; if it was lossless inside the MKV, this is the first lossy step. Either way it is hard to hear for normal listening.