Convert MKV to MP3, Free
Upload your MKV file and get a MP3 in seconds. No account, no watermark.
How to convert MKV to MP3
MKV (Matroska Video) is a flexible container that can hold multiple video, audio, and subtitle tracks. Extracting the audio track as an MP3 is useful when you want to keep the soundtrack from a video lecture, concert recording, or movie without storing the video. MP3 is universally playable and much smaller than the original MKV.
BoltConverter extracts the audio stream from your MKV file on its servers and encodes it as MP3. If the MKV contains multiple audio tracks, the first (usually default) track is used. The server processes the file without re-encoding the video, making audio extraction efficient.
Upload your MKV file
Click the upload area or drag your .mkv file onto the page. Large MKV files are supported up to the size limit shown.
Audio extraction runs on the server
The server pulls the audio stream from the MKV and encodes it as MP3.
Download the MP3
Save the MP3 file. It contains the audio from your MKV and plays on any audio device.
Frequently asked questions
Does this extract only the audio, not the video?
Yes. This converter produces an MP3 audio file. The video stream from the MKV is not included.
What if my MKV has multiple audio tracks?
The first audio track (typically the default language) is extracted. If you need a specific secondary track, specialized tools with track selection are needed.
Will the audio quality change?
The audio is decoded from whatever codec the MKV uses (often AAC, AC3, or DTS) and re-encoded as MP3. Some quality loss occurs in this step; the output quality depends on the bitrate used.
How large can the MKV file be?
The file size limit is shown on the upload page. MKV files for full movies can be several gigabytes, which may exceed the limit.
Can I also convert MKV to other audio formats?
BoltConverter has dedicated converters for other output formats. Look for MKV to AAC or MKV to WAV if you need a different audio format.