Convert MKV to WEBM
Convert MKV files to WEBM locally, completely free and with maximum privacy.
Drag and drop your files here
or click to browse local files (large files supported, limited only by browser RAM)
Upload FilesPlatform Statistics
How to convert MKV to WEBM
- Drop your .mkv files above, or click Upload Files. You can add many files at once.
- WEBM is already selected as the output. Open the settings (gear icon) to fine-tune the result.
- Click Convert All. FFmpeg runs inside your browser through WebAssembly; nothing is uploaded.
- Download your .webm files as soon as each one finishes.
What to know about MKV to WEBM conversion
- The video is re-encoded to VP8 video and Opus audio so it plays wherever WEBM is supported, and odd frame sizes are adjusted automatically.
- You can change the resolution, frame rate, playback speed and quality (CRF) before converting.
MKV vs WEBM
| Feature | MKV (Matroska Video) | WEBM (WebM Video Container) |
|---|---|---|
| Codecs used by PureConverter | H.264 video and AAC audio | VP8 video and Opus audio |
| Best for | movies with several audio and subtitle tracks | web video with open, royalty-free codecs |
| Opens in | VLC, mpv and most media players, Plex and most smart TVs | all modern browsers and VLC |
MKV (Matroska Video): A flexible, open-standard video container format that can hold unlimited video, audio, picture, or subtitle tracks.
WEBM (WebM Video Container): An open, royalty-free media file format designed for sharing video content directly on HTML5 web pages.
Conversion options
- Resolution: original, 1080p, 720p, 480p or 360p
- Frame rate and playback speed (0.5× to 2×)
- Quality presets or a custom CRF value, and lossless mode
- Audio bitrate, sample rate and channels
Frequently asked questions
Is it safe to convert MKV to WEBM here?
Yes. Your files are processed entirely on your own device by WebAssembly code running in the browser. They are never uploaded, so nobody else can see them, and the converter keeps working even if your connection drops after the page loads.
Is there a file size limit?
There is no server-side limit. The only limit is the memory available to your browser, typically 1.5–4 GB on desktop computers.
Can I convert several MKV files at once?
Yes. Add as many files as you like; they are converted in parallel according to your device's CPU cores, and you can apply the same settings to all of them.
Related conversions
Need the opposite? Convert WEBM to MKV.
Convert MKV to other formats
- MKV to MP4
- MKV to MP3
- MKV to WEBP
- MKV to GIF
- MKV to WAV
- MKV to MOV
- MKV to M4A
- MKV to FLAC
- MKV to AAC
- MKV to OGG
- MKV to OPUS
- MKV to AVI
Convert other formats to WEBM
- MP4 to WEBM
- MOV to WEBM
- AVI to WEBM
- WMV to WEBM
- FLV to WEBM
- M4V to WEBM
- MPEG to WEBM
- TS to WEBM
- 3GP to WEBM
- OGV to WEBM
See every MKV converter and WEBM converter, or browse the full converter directory.