Convert MKV to WebM
The tracks are usually re-encoded, which costs a little quality. If the MKV already carries codecs WebM accepts, they are copied as they are and nothing is lost.
They open in the converter with WebM selected.
Browse filesFiles stay on your device.
What changes
Only if your MKV already has AV1, VP9 or VP8 video with Opus or Vorbis audio does WebM accept it as it is, so the converter copies the tracks without re-encoding, in seconds and with no loss. If not, or if you change the quality, size, scale or trim, the video is decoded and compressed again, and loses a little more detail.
If it’s copied, it’s about the same size as the MKV: only the container changes. If it’s re-encoded, the size stays about the same.
Your browser may not be able to open MKV files, but the converter reads the file itself, so it can still convert it.
When it’s worth it
Choose WebM for: Websites and browser playback. Royalty-free, and plays in every modern browser.
Stay with MKV for: Video collections with several audio tracks and subtitles.
How to convert MKV to WebM
- Drop the MKV files on this page, or browse for them. Up to 200 at once.
- The converter opens with the files loaded and WebM selected.
- Press Convert, then save each file or all of them as a ZIP.
Questions
Does converting MKV to WebM lose quality?
Usually a little, because the video is compressed again. Only files that already carry a codec WebM accepts are copied without loss.
What is the WebM format?
The container Google designed for the web, carrying VP8 or VP9 video with Opus or Vorbis audio. It’s royalty-free, which is why open-source projects and most browsers prefer it.
What is the MKV format?
Matroska, an open container that can hold any codec in separate tracks, with subtitles as real tracks instead of burned-in text. That flexibility is why it’s the favorite for archiving and for fansubs.
Are the files uploaded?
No. The file is opened in this tab, converted here and saved from here. There’s no account and no watermark.
How many files can be converted at once?
Up to 200 per batch and about 2 GB per file, within the memory this device has available.