MKV to FLAC Converter
Extract audio from MKV as FLAC for lossless archival. MKV files sometimes already contain FLAC audio, making this a direct stream copy with zero quality loss.
If the MKV contains FLAC audio, extraction is lossless. For other audio codecs, the decoded audio is stored in FLAC format.
How to Convert MKV to FLAC
- 1
Upload your MKV file.
- 2
Select FLAC output.
- 3
Click Convert and download.
MKV vs FLAC — Format Comparison
| Feature | MKV | FLAC |
|---|---|---|
| Full Name | Matroska Video | Free Lossless Audio Codec |
| Type | Video | Audio |
| Codec | H.264 / H.265 / VP9 / AV1 | FLAC |
| Lossless | No | Yes |
| Extension | .mkv | .flac |
| Best For | High-quality video archival | Audiophile music collections |
MKV Strengths
- Open standard with no licensing fees
- Supports unlimited tracks (audio, subtitles, video)
- Excellent for high-quality video with multiple languages
FLAC Strengths
- 100% lossless — bit-for-bit identical to original
- Open source and royalty-free
- 50-60% smaller than uncompressed WAV
Frequently Asked Questions
When to Convert MKV to FLAC
- Lossless audio extraction from high-quality MKV files
- Archiving audio from media libraries
- FLAC system compatibility
Related Conversions
About Our MKV to FLAC Converter
This converter uses FFmpeg compiled to WebAssembly (WASM) to transform your MKV files into FLAC format entirely inside your web browser. When you select a file for conversion, the processing happens locally on your device. Your file is never uploaded to any server, never transmitted over the internet, and never stored anywhere outside your own computer. This privacy-first architecture makes our tool safe for confidential and sensitive content — including legal recordings, medical files, financial presentations, personal media, and any other material you would not want on a third-party server.
The conversion process works by decoding the MKV input using FFmpeg's highly optimized decoders, then encoding the output in FLAC format with carefully tuned settings that balance quality and file size. When possible, the tool uses stream copy mode to remux (rewrap) compatible streams without re-encoding, which preserves the original quality with zero generational loss. When re-encoding is necessary due to codec differences between the two formats, the converter uses high-quality encoding settings to minimize any visible or audible quality reduction.
Supported input formats include MP4, MOV, AVI, MKV, and WebM for video, with automatic detection of the codecs and parameters inside your source file. The output is optimized for maximum compatibility with modern devices and platforms including Windows, macOS, Linux, iOS, Android, smart TVs, and all major web browsers.
Why browser-based conversion is safer: traditional online converters require you to upload your file to a remote server, where it is processed by third-party infrastructure and then made available for download. This workflow exposes your data to interception during upload, unauthorized access on the server, unclear data retention policies, and potential data breaches. Professionals in regulated industries such as healthcare (HIPAA), legal (attorney-client privilege), and finance (SOX, GDPR) often cannot use server-based converters without violating compliance requirements. Our WebAssembly-powered approach eliminates all of these risks by ensuring your data never leaves the browser sandbox on your own device.
The tool handles files up to 500 MB on desktop browsers and 200 MB on mobile devices. No account registration, no software installation, and no recurring subscription is required. Conversion typically completes in seconds for small files and a few minutes for larger ones, depending on your device's processing capabilities. Once the conversion is finished, you can download the result immediately and the source data is discarded from browser memory.