Convert MKV to WEBM online in seconds — free, with no sign-up. WEBM is lossy and ideal for efficient web video in Chrome, Firefox and Edge. Your files are encrypted and deleted automatically after 24 hours.
MKV
Matroska Video — A flexible container that holds multiple audio, video and subtitle tracks.
WEBM
WebM — A royalty-free web video format (VP8/VP9) that's smaller than H.264 at equal quality.
How to convert MKV to WEBM
- 1Upload your MKV file
Click “Choose a file” or drag and drop your MKV file onto the page — no sign-up or email needed.
- 2Convert to WEBM
WEBM is already selected as the output. Open Options to fine-tune quality if you like, then click Convert.
- 3Download your WEBM file
Your WEBM file is ready in seconds — click Download to save it. Files are automatically deleted after 24 hours.
MKV vs WEBM
| MKV | WEBM | |
|---|---|---|
| Full name | Matroska Video | WebM |
| Type | Video | Video |
| Compression | Lossy | Lossy |
| Best for | archiving films with multiple tracks; converted to MP4 for compatibility | efficient web video in Chrome, Firefox and Edge |
Frequently asked questions
Does converting MKV to WEBM lose quality?
Both MKV and WEBM use compression, so re-encoding discards a little more data. For a single conversion the change is virtually invisible; just avoid repeatedly re-converting the same file.
What's the difference between MKV and WEBM?
Matroska Video (MKV) is lossy and best for archiving films with multiple tracks; converted to MP4 for compatibility. WebM (WEBM) is lossy and best for efficient web video in Chrome, Firefox and Edge. Convert MKV to WEBM when you need a video for efficient web video in Chrome.
Is the MKV to WEBM converter free?
Yes — converting MKV to WEBM is completely free. There's no watermark, no sign-up and no email required, and you can convert as many files as you like.
Are my MKV files private and secure?
Yes. Your uploads are encrypted in transit, processed privately, and automatically deleted within 24 hours. We never share, sell or look at your files.
Can I convert MKV to WEBM on iPhone, Android, Mac or Windows?
Yes. The converter runs entirely in your browser, so it works on any device — iPhone, iPad, Android, Mac, Windows or Linux — with nothing to download or install.
How long does it take to convert MKV to WEBM?
Most files convert in a few seconds. Larger files take a little longer, and your upload speed is usually the limiting factor. There's no queue and no waiting for an email.
What else can I convert MKV files to?
Besides WEBM, you can convert MKV to AAC, AVI, FLAC, FLV, GIF, JPG and more — see the full list of MKV conversions below.
Other conversions
Last updated July 2026