Free MKV to MP3 Converter One audio track out, nothing uploaded
Turn an MKV into an MP3 in your browser. Matroska is the container people end up with after a disc rip, a stream recording or an anime release, and it very often carries more than one audio track. This page extracts a single track and re-encodes it to a 128 kbps MP3, so read the part about track selection before you convert a whole folder. The file is opened locally and never sent to us.
- Nothing uploaded
- 128 kbps MP3
- 20 files per batch
Convert MKV to MP3
MP4, MOV, M4V, MKV, AVI, WMV, WebM, TS, MTS and more
Up to 20 clips at once
Privacy-first. No uploads. If this helps, share it.
- Your library stays on your machine
FFmpeg compiled to WebAssembly does the work inside this tab. That matters more than usual here, because an MKV is normally something you ripped, recorded or downloaded yourself, and it is nobody else's business.
- Honest about the track it takes
One audio track comes out and there is no track picker on this page. The choice is made automatically, so if your MKV holds an original language track, a dub and a commentary, check the result before you delete anything.
- 20 files per batch, 1 GB each
Queue a season folder in one go. Files run one after another because the browser build is single threaded. The picture is never decoded, so this is much quicker than a video conversion, but a long recording still takes minutes rather than seconds.
How to convert MKV to MP3
Add your MKV, let the browser pull the audio out, then download the MP3. The output is 128 kbps at 44.1 kHz, the video is discarded, and the original MKV on your disk is not touched. The catch worth knowing up front: an MKV can carry several audio tracks and only one of them ends up in the MP3.
- Add your MKV files
- Audio is pulled out locally
- Download the MP3
MKV vs MP3: what actually changes
Matroska is a container built to hold as much as you want to put in it: video, several audio tracks, subtitles, chapters, fonts and attachments. MP3 is the opposite, one audio stream and almost nothing else. Converting is less a format change than a decision about what to throw away, so it helps to see the two side by side.
| What changes | MKV source | MP3 result |
|---|---|---|
| Container | Matroska, an open container that can wrap almost any codec and any number of streams | A plain .mp3 file, a single audio stream with no room for extras |
| Video | Usually H.264 or H.265, sometimes VP9 or MPEG-2, and normally most of the file size | Gone. There is no picture in the output and no way to get it back from the MP3 |
| Audio codec | AC-3, E-AC-3 or DTS from disc sources, AAC from stream recordings, sometimes FLAC or Opus | MP3 at 128 kbps and 44.1 kHz, re-encoded from whatever the source track was, with surround folded down to stereo |
| Audio tracks | Often several: original language, one or more dubs, a commentary, a stereo mix next to a 5.1 mix | Exactly one. FFmpeg chooses it automatically, often the first track in the file, and this page has no selector |
| Size | A ripped film or episode is commonly hundreds of megabytes to several gigabytes, and anything over 1 GB is past what this page accepts | Roughly 1 MB per minute at 128 kbps, so a two hour film lands near 115 MB |
You can drop something that is not an MKV in here as well. It is converted anyway and the result is named for what actually arrived, so an M4V or a TS that got saved with the wrong habit still works.
Why pull audio out of an MKV at all
The reason is usually mundane. You have a recorded set, a concert capture, a commentary track or a talk sitting inside a multi gigabyte Matroska file, and you want it on a phone, a car stereo over USB or in an audio editor. None of those want the whole container with a 5.1 stream and three subtitle tracks in it. Dropping the video removes almost all of the size, and MP3 is the format that plays without an argument on hardware that has never heard of Matroska. What you give up is real: the picture, the subtitles, the chapter marks and every audio track except the one that gets picked.
There is also a quality cost worth saying out loud. Your MKV audio is usually already lossy AC-3 or AAC, and this re-encodes it to 128 kbps MP3, so you are compressing something that was compressed once already. Nothing here can improve on the source. It is fine for speech and background listening, and it is not the way to archive a soundtrack.
What the MP3 will and will not do
MP3 is the safe end of the trade. Car stereos over USB, old iPods, phones, smart speakers, Plex and Jellyfin audio libraries, podcast apps, transcription services and every editor will take it without a converter in between. The things that stop working are the things Matroska was carrying for you.
It plays anywhere audio plays, including hardware far too old to know what Matroska is.
Subtitles, chapters and the other audio tracks do not survive. A 24 minute episode becomes one flat MP3 with nothing to skip between.
It cannot rescue a protected file. Anything with DRM on it, an iTunes purchase for example, simply fails, and this tool cannot trim, cut or edit, so a two hour rip becomes a two hour MP3.
Extract MKV audio in three steps
All of it happens in this tab.
Add your MKV files
Drop them in or browse your device. Up to 20 at a time and 1 GB each, which covers most episodes and a good share of films.
Leave the To dropdown on MP3
The same converter can output MP4 instead if you decide you want the picture after all, and switching is one click rather than another page. That path keeps the video, and because MKV streams often fit into MP4 as they are, it is frequently a near instant rewrap rather than a full re-encode.
Download and listen to the first few seconds
Since you do not get to choose the track, a quick check tells you straight away whether you got the language you expected or somebody's commentary.
Why use this one
It is a narrow tool. Worth knowing where it is good and where a desktop program does the job better.
The video is never decoded
Extraction skips the picture entirely, so it does not crawl the way a full video re-encode does in a single threaded browser build. The audio itself is still re-encoded end to end, so a three hour recording takes a few minutes, and reading a 1 GB file into memory is the slow part on a phone.
A folder at a time
Twenty files per batch, so a whole season or a set of recorded talks goes in at once and you collect the MP3s one by one or as a zip.
It reads what MKV really contains
The bundled FFmpeg is a full GPL build, so it demuxes Matroska and decodes the audio codecs that turn up in rips and recordings, including AC-3, E-AC-3, DTS, AAC, FLAC and Opus. The video codec is irrelevant here because it gets dropped.
When you should use something else
If you specifically need the third track, the commentary, or the 5.1 mix kept intact, use MKVToolNix or FFmpeg on your desktop. Those let you list the tracks and name the one you want, and this page deliberately does not.
An MKV collection is a personal collection
MKV files come from ripped discs, recorded streams, camcorder archives, Plex libraries and downloads. Handing one of those to an upload based converter means a stranger's server now holds a copy of a file you never meant to publish, and probably knows its name too.
Here the extraction runs in the page through WebAssembly. There is no upload step, no queue, no temporary copy on our side and no account to attach a history to. Close the tab and there is nothing left to delete.
What that means in practice
- The MKV is read by your browser and stays on your disk
- We never receive the file, its name or its duration
- No account, no watermark, no audio stamped into the MP3
- Your own CPU and memory do the work, so a 1 GB file is heavy on a phone
MKV to MP3 troubleshooting
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Open toolFrequently asked questions
Add the MKV to the box at the top of this page, let your browser extract the audio, then download the MP3. There is no signup, no upload and no watermark.
Last reviewed in 2026 for browser-based audio extraction from Matroska files.