MKV to MP3 converter online — free
Quick answer Extract the soundtrack from an .mkv (Matroska) video as MP3 or WAV — up to 50MB.
Pull audio from MP4/MOV/MKV/WebM. Optional start/end so you only extract what you need. Up to 50MB.
Free to try · No signup required · Commercial use allowed · How we test · About VoxCraft
Convert MKV to MP3 online for free with VoxCraft. Upload an .mkv video (up to 50MB), pick MP3 or WAV, and download only the audio — no install and no signup on the free tier.
MKV (Matroska) is a flexible video container used for screen recordings — OBS can record straight to it — as well as for videos you've downloaded or ripped from your own discs. Many audio tools and phones don't accept it, so extracting the audio is the practical way to reuse a voice-over, a talk or music you have the rights to.
MKV files can hold several audio tracks; this tool extracts a single main audio track rather than all of them. A 50MB cap applies to uploads, so for long recordings cut the video into shorter parts first.
Respect copyright: extract audio only from material you own or are licensed to use.
How it works
- Upload your .mkv file (up to 50MB).
- Pick MP3 for sharing or WAV for editing.
- Optionally set start and end times for just part of the file.
- Tap Extract audio and download.
Who uses this
Screen recordings
Pull the narration from an OBS recording into its own audio file.
Talks and tutorials
Make an audio-only version of a long talk you can listen to.
Transcription prep
Extract the audio, then run it through the transcribe tool.
Tips for better results
- Use WAV when you plan to clean noise or edit; MP3 for sharing.
- If the file is too large, split the video into shorter parts first.
- Normalize after extracting if the recording is too quiet.
- Only the main audio track is extracted.
Frequently asked questions
What is an MKV file?
A Matroska video container that can hold video, multiple audio tracks and subtitles.
Which audio track is extracted?
The main/default audio track.
What is the size limit?
50MB per video.
Is it free?
Yes within free-tier limits, with no account required to start.
Is it OK to extract audio from any video?
Only from videos you own or have permission to use.