MKV Converter Free & Private
The flexible open container for everything. Convert Matroska Video files entirely in your browser — no upload, no account.
About Matroska Video
MKV (Matroska Video) is an open-standard container format that can hold virtually any combination of video, audio, and subtitle tracks in a single file. Named after Russian matryoshka dolls, it's designed to be future-proof and extensible. MKV is the preferred format for high-quality video archival, Blu-ray rips, and media libraries managed by Plex, Jellyfin, or Kodi.
Technical details
| Container | Matroska (.mkv, .mka, .mks) |
| Video codecs | H.264, H.265, VP8, VP9, AV1, MPEG-4, Theora |
| Audio codecs | AAC, Opus, Vorbis, FLAC, AC-3, DTS, MP3, PCM |
| Max resolution | No formal limit |
| Streaming | Streamable Matroska (WebM is a subset) |
| Metadata | Extensive (tags, chapters, attachments, cover art, fonts) |
Best for
Media libraries, high-quality archival, multi-language video with subtitles
Advantages
- Supports virtually every codec in existence
- Multiple audio and subtitle tracks in one file
- Chapter support for easy navigation
- Open standard — no patents or licensing fees
Limitations
- Less broad device support than MP4
- Not supported natively by most web browsers
- Some smart TVs and consoles can't play MKV
Convert other formats to MKV
MKV compatibility
VLC, Plex, Jellyfin, Kodi, mpv, Windows 10+; limited iOS/browser support
Why privacy matters for file conversion
Most online converters upload your files to remote servers where they may be scanned, stored, or shared. This tool is different — the conversion runs in your browser via WebAssembly or the WebCodecs API. Your files stay on your device. Always.
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Frequently asked questions
Many modern smart TVs support MKV, but older models may not. If your TV can't play MKV, use a media server like Plex (which transcodes on the fly) or convert to MP4.
MKV supports more codecs, more tracks, and chapters — making it better for archival and media libraries. MP4 has broader device compatibility. For maximum portability, use MP4; for flexibility, use MKV.
Yes, completely free with no file limits. The conversion engine runs directly in your browser — we have zero server costs for processing, so we can offer it at no charge.
Your file never leaves your device. The conversion engine runs 100% in your browser using WebAssembly or the WebCodecs API. We have no access to your files — no uploads, no logs, no data collection whatsoever.
On desktop browsers (Chrome, Firefox, Edge) files up to 500 MB convert reliably. On Safari (macOS) the practical limit is around 200 MB. On iPhone and iPad, keep files under 50 MB — iOS enforces tight memory limits for browser-based processing.
On your first visit, the browser downloads the conversion engine (24–50 MB depending on which backend is used). This is cached locally, so subsequent conversions load much faster.
Chrome, Edge, and Brave use hardware-accelerated WebCodecs when the format is supported — this is 5–10× faster than software encoding. For unsupported formats the tool falls back to ffmpeg.wasm, where Firefox typically performs best.
Utterly is a privacy-first transcription app for Apple devices. It uses on-device AI to transcribe and translate audio — no cloud, no subscription required to start. This free converter is brought to you by the Utterly team.