MKV to MP3 converter
Pick an MKV and keep only its sound, as an MP3. This tab does the work on your own computer, so the recording stays where it is.
Extract MP3 audio from an MKV
MKV to MP3, in your browser
Drop a file here or choose one. It stays on this device. Up to 500 MB and 2 hours of sound.
Your browser does the conversion. Open your browser’s network tab while converting to check that the file is not uploaded.
The MP3 encoder is lamejs, open source under the LGPL. See open-source licenses.
Your MKV never leaves your device. The browser decodes its sound track on your machine and the MP3 is built in this tab, so Textspert gets no copy and no account is involved.
Which MKV sound tracks convert
MKV, short for Matroska, can hold almost any kind of sound, so the codec inside decides. We tested each one in Chromium.
| Sound in the MKV | Usually from | Converts here |
|---|---|---|
| AAC | OBS Studio, phone and camera exports | Yes |
| Opus | Browser and WebM-style recorders | Yes |
| Vorbis | Older open-source tools | Yes |
| MP3 or FLAC | Music and archive copies | Yes |
| AC-3, E-AC-3 or DTS | Movie and TV releases with surround sound | No, the browser can’t decode it |
Surround tracks that do decode, like 5.1 AAC, fold down to stereo with the center channel kept in the mix, so voices survive.
Recordings from OBS and other screen tools
Streamers and teachers often record to MKV in OBS Studio, because a crash or a power cut leaves the file readable up to that moment. The catch is that lots of apps won’t open MKV. An MP3 plays in any podcast editor, phone or chat app.
OBS can record several audio tracks into one MKV, say your microphone on one and game sound on another. The browser decodes only the first track, so the MP3 holds whatever OBS put there. For a different track, remux the file in OBS or pick that track in your editor first.
How to convert MKV to MP3
Drop in the MKV
Or click to choose it. Files up to 500 MB and 2 hours of sound are fine.
Wait while it encodes
A progress bar tracks the MP3 as it’s written. Expect your fan to spin up on a long stream recording.
Download
Save the MP3. It keeps the MKV’s file name.
The MP3 you get
Every file comes out as a 128 kbps MP3 at 44.1 kHz, roughly 58 MB an hour. That suits voice, commentary and casual listening. If you’re keeping game music or a concert for its sound, hold on to the MKV and treat the MP3 as the copy you share.
A two-hour stream sits right at the limit. Cut longer ones into parts in your editor, or split the recording in OBS next time.
From MKV to a transcript
Textspert transcribes MKV files directly, so a recorded stream, lecture or call becomes searchable text with labels for up to 4 voices per file. Start at video to text, or make captions with the subtitle generator. Other video types go through video to MP3.
Turn the recording into text
Launching November 2026
MKV to MP3 questions
Is the MKV converter free?
Yes. Nothing to install and no account, since the work runs on your own computer.
Why does my movie MKV fail?
Movie files usually carry AC-3, E-AC-3 or DTS surround sound, which browsers can’t decode. Recordings from OBS and similar tools use AAC or Opus and convert fine.
Is the MKV uploaded?
No. It’s read from your disk and converted inside the browser tab.
Can I choose which audio track to convert?
Not yet. The browser decodes the first sound track in the file.
Does it work on WebM files?
Yes. WebM is built on the same Matroska format. The video to MP3 page lists WebM in its file picker.
Can Textspert transcribe an MKV with AC-3 sound?
Yes. Uploads for transcription are decoded on Textspert’s servers, not in your browser, so formats the converter can’t read still work there.
Other tools for recordings
- Video to MP3Keep the soundtrack of MOV, MKV, WEBM or MP4 video as an MP3.
- MP4 to MP3Pull the audio out of an MP4 as an MP3, right in your browser.
- Video to textGet a transcript or SRT and VTT subtitles from MP4, MOV, MKV and other video files.
- ToolsEvery transcription tool on one page.
Compare plans on the pricing page, or read our short privacy promises.
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