Convert any video file to FLAC format online for free. Fast, secure, and easy-to-use video to FLAC converter with no software installation required.
or click below to browse
Max file size: 50 MBMax duration: 30 min
Sign up for increased limitsA free account gets you up to 50 MB and 30 min.
Drag and drop your MKV file, or click to browse for it.
Choose FLAC as the output and click Convert. The conversion runs on our servers, so your device does none of the work.
Download your converted file instantly. The download link expires in 1 hour for security.
Our powerful servers process your files quickly, delivering converted files in seconds.
Convert your files completely free with no hidden costs or subscription fees.
Your file is used only to make your conversion. It is never published or shared, and the download link expires after one hour.
Works directly in your web browser. No software download or installation required.
How the two formats differ on the things that change your result.
| Specification | MKV (source) | FLAC (result) |
|---|---|---|
| Container | Matroska | FLAC |
| Developed by | Matroska.org | Xiph.Org Foundation |
| Introduced | 2002 | 2001 |
| Audio codecs | AAC, FLAC, Opus, AC-3, DTS | FLAC |
| Compression | Depends on codec | Lossless (compressed) |
| Approx. file size | 60–300 MB per minute | 5–7 MB per minute |
| Metadata / tags | Container tags | Vorbis comments |
| Licensing | Royalty-free | Royalty-free |
| Plays natively on | Native: Windows · Needs a player: macOS, iOS, Android, Smart TVs | Native: Web browsers, Windows, macOS, iOS, Android · Needs a player: Smart TVs |
| Best for | media archives, multi-language releases, home theatre | long-term archiving, audiophile listening, CD ripping |
Only the soundtrack survives: the video stream is dropped, and the AAC audio inside the MKV file is re-encoded as FLAC.
The size drop is dramatic because the video stream is where nearly all the data lives. A minute of MKV runs around 180 MB; the extracted FLAC is roughly 6 MB per minute.
FLAC is lossless, but the ceiling is the soundtrack already inside the video. That track is usually AAC, which is lossy, so FLAC preserves it exactly rather than improving it.
Any subtitle tracks in the source are not part of an audio file and are dropped during extraction.
The source can carry more than one audio track, for example alternate languages or a commentary. Extraction takes the primary track.
This tool takes the audio track from inside a MKV file, a Matroska container from 2002, and saves it on its own as FLAC. Everything visual is left behind.
MKV comes from Matroska.org and dates to 2002. It usually holds H.264, H.265, VP9, or AV1 video with AAC, FLAC, Opus, AC-3, or DTS sound, and those streams set the ceiling for anything converted out of it.
FLAC comes from Xiph.Org Foundation and dates to 2001. It carries losslessly compressed audio (FLAC), and without installing anything it plays on web browsers, Windows, macOS, iOS, and Android.
After converting your file, you can use Scriptivox transcription services to convert your audio to text. Perfect for meetings, interviews, podcasts, and more.
Quick access to the most commonly used file conversions
And many more format conversions supported