Convert MKV to WebM
Turn your MKV file into a WebM that plays where you need it, with nothing to install.
- Free to start
- Nothing to install
- Up to 1GB
How to convert MKV to WebM
Upload your MKV file
Drag and drop a MKV file to turn into WebM, or click to browse. Anything under 1GB, and nothing is installed.
Confirm WebM as the output
WebM is already selected, so there is nothing to configure. Switch to another format in the panel if MKV needs to go somewhere else.
Convert and download
We convert the MKV on our servers, usually in under a minute. Create a free account to download the WebM.
Why convert MKV to WebM?
MKV (Matroska) is an open container that can hold any codec plus unlimited audio tracks, subtitle tracks and chapters. That flexibility makes it great for archives and useless for sharing.
The practical problem: Browsers, phones and social uploads reject MKV almost universally. Editing tools often refuse to import it, or import picture without audio. Nobody can preview it without installing VLC first.
WebM solves that. Streams natively in Chrome, Firefox and Edge with no plugin. VP9 delivers smaller files than H.264 at the same visual quality, which cuts bandwidth on a busy page.
Container
Typical codecs
Best for
Plays on
File size
| Feature | MKV | WebM |
|---|---|---|
| Container | Matroska | WebM (Matroska-based) |
| Typical codecs | Almost anything: H.264, HEVC, AV1, VP9 | VP8 / VP9 / AV1 video, Opus audio |
| Best for | Archiving with multiple audio and subtitle tracks | Web embeds and browser recordings |
| Plays on | VLC and desktop players; rarely anywhere else | Chrome, Firefox and Edge; hit and miss elsewhere |
| File size | Depends entirely on the codec inside | Very small at the same quality |
MKV to WebM questions
Is the MKV to WebM converter free?
Yes. Convert and preview the result for free, then create a free account to download it. There is no per-file charge and no watermark on the WebM itself beyond the free-plan badge.
Do I need to install any software?
No. The conversion runs on our servers and you use it from a browser tab, so it works the same on Windows, macOS, Linux, iPhone and Android. Nothing to install at either end. Where MKV plays: VLC and desktop players; rarely anywhere else. Where the WebM you get back plays: Chrome, Firefox and Edge; hit and miss elsewhere.
Does converting MKV to WebM reduce the quality?
Converting re-encodes the video, so it is not bit-for-bit identical. We encode at a high quality target, which keeps the result visually indistinguishable from the MKV on normal viewing. What changes is the container and the codec. WebM holds: VP8 / VP9 / AV1 video, Opus audio. Converting the same file back and forth repeatedly will eventually show, so keep your original.
How large a file can I convert?
Anything under 1GB per upload, which is more footage in some formats than others. MKV: Depends entirely on the codec inside. WebM coming back: Very small at the same quality. For anything bigger, trim or compress it first, both are free tools here.
Is my file kept private?
Your upload is processed and then held only as long as your project needs it. Nothing is published, indexed or shared unless you create a share link yourself.
Other formats
Everything else you can do here.
Every conversion for a format
Convert to MP4
Convert to WebM
Convert to AVI
Convert to WMV
Convert to 3GP
Convert to M4V
Convert to MPEG
Convert to GIF
Convert to MP3
Convert to WAV
Convert MKV to WebM now
Free, nothing to install, and the file stays open in a full video editor afterwards.