Convert WEBM to MKV right in your browser
Free and unlimited, and nothing is uploaded: it all runs in your own browser. Open Video Converter
What changes when you convert WEBM to MKV
- Both formats are lossy. Re-encoding adds a second generation of loss, so keep quality high (80+) unless size matters more than fidelity.
- WEBM video transparency is flattened onto a solid background because MKV video has no alpha channel.
- Both formats support animation; animated input stays animated where the target truly supports it.
- MKV video encoding exposes a quality control; around 80 is the usual sweet spot.
How to convert WEBM to MKV
- Add your WEBM file — drag it onto the page or choose it. It stays on your device.
- Pick MKV as the output format and set the quality slider.
- Press convert and download the result — individually or as one ZIP.
Questions
How do I convert WEBM to MKV for free?
Add your WEBM file on this site, choose MKV, and press convert. The whole conversion runs in your own browser — nothing is uploaded — and the MKV file downloads straight from your device.
Will converting WEBM to MKV lose quality?
Both formats are lossy. Re-encoding adds a second generation of loss, so keep quality high (80+) unless size matters more than fidelity.
What happens to transparency when I convert WEBM to MKV?
WEBM transparency is flattened onto a solid background, because MKV has no alpha channel. Pick WEBM-friendly targets like PNG or WEBP to keep transparency.