MKV to WEBM converter
Convert MKV to WEBM in seconds, free and unlimited. No upload, no sign-up, no watermark: your video never leaves your device.
Last updated
Quick answer: To convert MKV to WEBM, add the MKV file to the iHateFiles MKV to WEBM converter and press Convert. The conversion runs in your browser, so the file is never uploaded, and it is free with no sign-up, watermark or size limit. An open, royalty-free format that browsers play natively.
Should you convert MKV to WEBM?
A safe conversion: MKV and WEBM are both lossless, so this is a change of container rather than a change to the picture.
Nothing is discarded
MKV and WEBM are both lossless, so every pixel survives the move intact. Convert back and forth as often as you like; the image does not degrade.
MKV and WEBM side by side
| MKV | WEBM | |
|---|---|---|
| Compression | Lossless | Lossless |
| Transparency | No | No |
| Animation | No | No |
| Written here | Yes | Yes |
What usually goes wrong
About the MKV. MKV and WEBM share a signature because WEBM is a restricted Matroska, so tools sometimes report one as the other. What matters is the codecs inside.
About the WEBM. A browser screen recording is usually a WEBM with a broken duration, so players show it as zero seconds or refuse to seek. Converting it to MP4 rewrites the header and fixes the seeking.
How to convert MKV to WEBM
- Add your MKV file. It is read from your disk and stays there.
- Check the settings. The output format is already set to WEBM.
- Press convert and the WEBM file is saved back to your device.
Questions
How do I convert MKV to WEBM?
Open this page, add your MKV file, and press convert. The file is decoded and re-encoded by your own browser and saved back to your device. Nothing is uploaded.
Is this MKV to WEBM converter free?
Yes, completely. There is no account, no sign-in, no watermark and no daily limit, because there is no server doing the work. Your own device does it.
Are my files uploaded anywhere?
No. There is no upload endpoint. The conversion runs inside this browser tab, so your file never leaves your device. You can open your browser's network panel and watch: nothing carrying your file is sent.
Is there a file size limit?
No fixed limit. Because the work happens on your machine there is no server quota. The only ceiling is your own device's memory, which for video means very large files may be slow.
Will converting to WEBM lose quality?
WEBM is a lossy format, so some detail is discarded. The quality control on this page decides how much. The default is set high enough that most people cannot see the difference.
Can I convert several MKV files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP.