Convert MKV to MP3
To convert MKV to MP3, add your .mkv file below and press the button: it's processed on your own device and you download the result, with nothing uploaded. It's free, needs no account, and works with files up to 500MB.
About converting MKV to MP3
MKV (.mkv) files can be converted to MP3 entirely in your browser — no software to install, no file upload, and no account required. The conversion runs on a WebAssembly build of ffmpeg directly on your device.
Technical comparison
| MKV | MP3 | |
|---|---|---|
| Category | video | audio |
| Compression type | Varies (codec-dependent — a container, not a codec) | Lossy |
| Typical file size | Varies — depends entirely on the codecs it wraps | Small — roughly 1MB per minute at 128–192kbps |
| Transparency support | Depends on the wrapped codec | N/A (audio) |
How to convert MKV to MP3 privately
Every step below runs on a WebAssembly build of ffmpeg inside this browser tab. Your .mkv file is never uploaded to a server — there's no network request carrying it anywhere.
Add your MKV file
Drag and drop, or click to select, a file (.mkv). It's read straight from disk into browser memory — no upload step exists.
Convert locally
FreePrivateConvert converts it to MP3 using a WebAssembly build of ffmpeg, entirely within this browser tab.
Download the result
Save your converted .mp3 file. It only ever existed in this tab's memory — closing the tab without downloading discards it completely.
Convert MKV to MP3 with ffmpeg (command line)
Prefer the terminal? This is the exact ffmpeg command this page runs for you:
ffmpeg -i input.mkv -vn -c:a libmp3lame -q:a 2 output.mp3- -i input.mkv
- Your MKV file.
- -vn
- Drop the video track and keep only the audio.
- -c:a libmp3lame
- Encode the audio as MP3 (LAME encoder).
- -q:a 2
- Variable-bitrate MP3 quality 2 on a 0-9 scale (lower is better; 2 is roughly 190 kbps).
- output.mp3
- The MP3 file to create. ffmpeg picks the container from this extension.
Don't have ffmpeg installed? You don't need it: use the converter at the top of this page. It runs the same conversion on your own device, and your file is never uploaded.
FAQ
- Is my file uploaded anywhere?
- No. Your file is read and processed inside this browser tab and never leaves your device. You can confirm it in your browser's developer tools: the Network tab shows no upload.
- Does converting MKV to MP3 reduce quality?
- MP3 is lossy and the video's soundtrack was already compressed, so this is a second lossy encode, at LAME's high-quality VBR setting (-q:a 2, around 190 kbit/s). Most listeners won't hear a difference, especially for speech.
- Is there a file size limit?
- Yes: 500MB per file. There's no account and no limit on how many files you convert.
- What's the difference between MKV and MP3?
- MKV (Matroska Video) and MP3 (MPEG-1 Audio Layer III) store data differently. MKV: varies (codec-dependent — a container, not a codec). MP3: lossy. MP3 is the most widely compatible lossy audio format — plays on essentially every device and app made in the last two decades.
- Why convert MKV to MP3?
- Common uses for MP3: Podcasts and audiobooks; Music distribution and downloads; Extracting audio from video. Universal hardware and software decoder support, making it the safest choice for compatibility.
- What MIME type does a .mp3 file use?
- audio/mpeg, the standard type for MPEG-1 Audio Layer III.
- What is the ffmpeg command to convert MKV to MP3?
- Run: ffmpeg -i input.mkv -vn -c:a libmp3lame -q:a 2 output.mp3. This is the exact command FreePrivateConvert runs for this conversion, so you can use this page instead of installing ffmpeg: it runs the same conversion inside your browser.
Learn more: What is an MKV file
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