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ConvertAnyVideo

MKV to WebM Converter

Convert MKV videos to WebM in seconds. Change resolution, quality and frame rate if you like — all in your browser.

or drop files here

Up to 1 GB per file · Files never leave your device

  • 100% free
  • No sign-up
  • No upload — private
  • No watermark

How to convert MKV to WebM

  1. Add your MKV files

    Click “Choose Files” or drag and drop your MKV videos onto this page.

  2. WebM is selected

    The output is already set to WebM. Open Advanced settings if you want to change the quality, resolution or length.

  3. Convert and download

    Click Convert. Your WebM file is ready in moments — nothing is uploaded.

About the formats

MKV

Matroska Video

MKV (Matroska) is a flexible open container that can hold several audio tracks, subtitles and chapters in one file. It is popular for movies and series.

WebM

WebM Video

WebM is an open, royalty-free format made for the web. It uses VP8/VP9 video with Opus or Vorbis audio and plays directly in modern browsers.

Frequently asked questions

How do I convert MKV to WebM?

Click “Choose Files” and select your MKV file (or drag it onto the page). WebM is already selected as the output, so just click Convert and download your WebM file when it’s ready.

Will I lose quality converting MKV to WebM?

When the video inside your MKV file is compatible with WebM, it is copied without re-encoding, so there is no quality loss at all. Otherwise it is re-encoded at high quality. You can pick the quality yourself in Advanced settings.

Is it safe to convert MKV files here?

Yes. Conversion runs inside your own web browser, so your files are never uploaded to our servers or anyone else’s. Nobody can see them, and nothing is stored after you close the tab.

Is the MKV to WebM converter free?

Yes, it’s completely free. There’s no sign-up, no watermark and no limit on how many files you convert. Each file can be up to 1 GB.

Can I convert several MKV files at once?

Yes. Add as many MKV files as you like and convert them in one go, then download them one by one or together as a ZIP file.

Convert MKV to other formats

Convert other formats to WebM