MKV to MP3 Converter
MKV files often carry several soundtracks at once. This converter lets you choose the one you want, mixes it down to stereo and saves it as an MP3 for your phone, car or music library.
Video to Audio
or drop MP4, MOV, MKV … files here ·
Max 95 MB per file· Up to 20 files· Deleted after 30 minutes
Files are processed on our servers and deleted after 30 minutes.
Keep the source rate unless a device or app asks for one. 44.1 kHz is CD standard, 16 kHz is enough for speech recognition.
Mono halves the size of lossless files and is fine for speech.
16-bit is CD quality. Choose 24-bit only if you will edit or master the audio.
Videos with several languages or a commentary have more than one track. 1 is the main track.
Optional. Seconds (e.g. 75) or minutes:seconds (1:15). Leave empty to start at the beginning.
Optional. Same format as the start time. Leave empty to keep everything up to the end.
How to use this tool
- 1
Add the MKV files
Upload up to 20 .mkv files, each up to 95 MB. Episodes, game captures and concert rips all work.
- 2
Choose the audio track
Audio track is 1, the first soundtrack stored in the file. Open Advanced settings and enter 2, 3 and so on for a dub, a commentary or a separate microphone track.
- 3
Extract to MP3
Press Extract to MP3. The result is a 256 kbps stereo MP3 named after the MKV it came from.
Pick the audio track, keep Stereo, press Extract to MP3. One soundtrack from the MKV becomes a 256 kbps MP3; the video, subtitles and other tracks are left behind.
Why MKV audio needs extra care
Matroska appeared in 2002 as an open container that accepts almost any codec, and the IETF published its specification as RFC 9559 in 2024. One .mkv can hold a video stream, several audio tracks in different languages, subtitles in a dozen languages, chapter markers and even attached fonts. That flexibility is why MKV is popular for film releases and long recordings, and why OBS Studio users like it: a crash mid-recording leaves a readable file.
For audio extraction, the flexibility means you have to make two decisions that an MP4 rarely asks for. First, which track: a film may list English 5.1, a dub and a director's commentary, and a gameplay capture may separate game sound from the microphone. Second, how many channels: surround tracks are mixed to stereo because the MP3 format stops at two.
The codec inside also varies. AC-3, DTS, AAC, Opus and FLAC are all common in MKV, and each one is decoded and re-encoded as MP3. If you want the film sound for listening while you travel, MP3 at 256 kbps is ideal. If you want to edit it, choose WAV, and if you want to keep the video too, MKV to MP4 changes the container without removing the picture.
Audio codecs each video container can hold
| from ↓ · to → | AAC | MP3 | Opus | Vorbis | FLAC | AC-3 |
|---|---|---|---|---|---|---|
| MKV | MKV to AAC: yes | MKV to MP3: yes | MKV to Opus: yes | MKV to Vorbis: yes | MKV to FLAC: yes | MKV to AC-3: yes |
| MP4 | MP4 to AAC: yes | MP4 to MP3: yes | MP4 to Opus: yes | – MP4 to Vorbis: no | MP4 to FLAC: yes | MP4 to AC-3: yes |
| WebM | – WebM to AAC: no | – WebM to MP3: no | WebM to Opus: yes | WebM to Vorbis: yes | – WebM to FLAC: no | – WebM to AC-3: no |
| AVI | – AVI to AAC: no | AVI to MP3: yes | – AVI to Opus: no | – AVI to Vorbis: no | – AVI to FLAC: no | AVI to AC-3: yes |
MKV
Matroska video
MKV is the Matroska multimedia container, an open-source format first released in 2002. It can hold nearly any video and audio codec plus unlimited audio tracks, subtitle tracks, chapters and attachments in one file. That flexibility makes it popular for films with several languages, screen recordings from OBS and long-term archiving. Phones, browsers, editors and some TVs do not support MKV, even when they support the codec inside.
- Compression
- Lossy or lossless
- Transparency
- –
- Animation
- –
- Introduced
- 2002 · Matroska project
MP3
MP3 audio
MP3 (MPEG-1 Audio Layer III) is a lossy audio format developed largely at the Fraunhofer Institute and standardised by MPEG in 1993. It removes sounds the ear is unlikely to notice, shrinking music to about a tenth of CD size at 128–320 kbps. All patents have expired, and every phone, car stereo, browser and media player supports it. Quality loss is audible at low bitrates and accumulates with re-encoding.
- Compression
- Lossy
- Transparency
- –
- Animation
- –
- Introduced
- 1993 · Fraunhofer IIS / MPEG
People convert MKV to MP3 to keep a single soundtrack, such as a concert, an episode's original language or a stream's voice track, out of a large multi-track file that phones and car stereos cannot read.
How to choose the right track in an MKV
See what is inside
Open the MKV in VLC and look under Audio → Audio Track, or load it into MediaInfo. Both list every audio stream with its language and codec, in the order the file stores them.
Count from 1
The first audio stream listed is track 1, the second is track 2. Subtitle and video streams are not counted. Enter that number in Audio track, up to 16.
Test with one file
For a season of episodes encoded the same way, convert one file, check the language, then upload the rest with the same setting.
MKV to MP3 questions
Which audio track does MKV to MP3 extract if I change nothing?
Track 1, the first audio stream in the file. In most releases that is the original language, but the MKV's default flag can point elsewhere, so the track a player starts with is not always number 1. If the MP3 is in the wrong language, run the file again with Audio track set to 2.
Can an MP3 keep the 5.1 surround sound of a movie?
No. MP3 as used by players and phones holds at most two channels, so a 5.1 AC-3 or DTS track is mixed down to stereo, which is why this page sets Channels to Stereo. Dialogue from the center channel stays audible in the mix.
Are MKV chapters kept in the MP3?
No. Chapter markers belong to the Matroska container and are not copied into the MP3. To split a concert into songs, use Start at and End at with the chapter times and extract each part separately.
Why is my voice missing from the MP3 of an OBS recording?
OBS Studio can write up to six audio tracks into an MKV, for example game sound on track 1 and the microphone on track 2. The MP3 only contains the track you pick, so set Audio track to the number of your microphone track, or to the mixed track if you set one up.
Is 256 kbps really needed for an MKV soundtrack?
For film music and concerts it is a safe choice, because the source is often a high-bitrate AC-3, DTS or lossless track. For a lecture or a podcast episode, 128 kbps sounds the same and makes a file half the size.
The MKV has a FLAC soundtrack. How do I keep it lossless?
Pick FLAC or WAV in the Convert to list instead of MP3, or use MKV to WAV. MP3 is always lossy, so it is the right choice for listening on the go, not for archiving a lossless source.
More ways to get audio from video
- MP4 to MP3 ConverterConvert MP4 to MP3 free: pull the sound out of a video as an MP3 that plays on any phone, car stereo or player. Pick the bitrate, trim, batch 20 files.
- MKV to WAV ConverterConvert MKV to WAV: pull one audio track from a Matroska video as PCM for editing. Lossless for FLAC and TrueHD tracks, 24-bit, surround or stereo.
- WebM to MP3 ConverterConvert WebM to MP3 online: turn browser recordings and web video into MP3 that plays in iTunes, car stereos and old players. 192 kbps, 44.1 kHz, 20 files.
- AVI to MP3 ConverterConvert AVI to MP3 online: extract the MP3, AC-3 or PCM sound from Xvid and DivX files, digital camera clips and dashcam footage. 192 kbps, 20 files per batch.
- MKA to MP3 ConverterConvert MKA (Matroska audio) to MP3. AC-3, DTS, FLAC, Opus or AAC inside is decoded and surround is downmixed to stereo. Up to 20 files, 95 MB each.
- MKV to MP4 ConverterConvert MKV to MP4 free online. Turns OBS recordings and Matroska files into H.264/AAC MP4 that iMovie, iPhones and smart TVs open. Up to 20 files.