Convert WEBM to MKV — Free, No Upload
Runs entirely in your browser. Nothing is sent to any server.
Video
Audio
Why convert WEBM to MKV?
WEBM and MKV are both widely used formats. Converting between them in your browser is instant, free, and private — no account needed, and your file never leaves your device.
What is WEBM?
WebM is Google's open-source video format, designed for web browsers. Common in screen recordings and downloaded web videos.
What is MKV?
MKV (Matroska) is a container that can hold multiple audio tracks, subtitles, and chapters. Popular for high-quality movie and TV rips.
Frequently asked questions
Is this WEBM to MKV converter really free?
Yes, completely free. No account, no credit card, no watermark, no file size limit imposed by a paywall. Convifi is free to use forever.
Is my file safe when I convert WEBM to MKV?
Your file never leaves your device. All conversion happens locally in your browser using WebAssembly. There is no upload to any server — not even Convifi's.
Does this work on iPhone, Mac, and Windows?
Yes. Because it runs in the browser, it works on any device — iPhone, Android, Mac, Windows, or Linux — as long as you have a modern browser like Chrome, Safari, Firefox, or Edge.
How long does WEBM to MKV conversion take?
Conversion time depends on your file size and device. Most files convert in under 30 seconds. Longer videos or high-resolution images may take a minute or two. Nothing is being sent over the network, so your connection speed has no effect.