Convert MKV to MP3
The soundtrack pulled out of the video — extracted privately on your own device, no upload involved.
Drop your video or audio here
or
MP4, MOV, WebM, MKV, AVI, MP3, WAV and more — any size, no upload
🔒 Files never leave your device — everything runs in your browser.
MKV is the archivist's container — long recordings, concert footage, lecture captures, multi-track rips. Often the part you actually return to is the audio: the talk, the set, the interview. Extracting it as MP3 gives you a small file that plays in every podcast app, car stereo, and phone on earth.
The tool decodes the MKV's audio track and encodes it to high-quality MP3, discarding the video entirely — which is why the output is a fraction of the original's size. Everything runs in your browser; a two-hour recording never has to upload anywhere to become a listenable file.
How it works
- Drop your file
Any common format, any size. Nothing is uploaded — the tool runs in your browser.
- Convert
Compatible files are repackaged instantly with zero quality loss; others are hardware-transcoded at high quality.
- Download
Your converted file is ready on your device — nothing to wait for, nothing to delete from a server.
Frequently asked questions
Which audio track is extracted if the MKV has several?
The file's primary audio track — the one a player selects by default. MKVs with multiple language or commentary tracks convert to a single MP3 of that default track.
How large is the MP3 compared to the MKV?
Small — at the high-quality setting used here, audio runs about 2.5 MB per minute, while the discarded video data is usually many times that. An hour-long MKV becomes an MP3 around 140 MB.
Is a long recording safe to convert in a browser?
Yes — the file is processed on your own device in streaming fashion, not uploaded. Length mostly affects how long the extraction takes, and audio-only encoding is fast.
Is my file uploaded to a server?
No. ConvertUno runs entirely in your browser on your own device. Your file never leaves your computer or phone — there is no upload at all.
Is it really free, with no watermark?
Yes. Processing happens on your device, so serving you costs us almost nothing — no watermark, no account, no file-size limit, no daily quota.