Convert WebM to MKV

Transform your open-source web video format by google into MKV format. Free, private, and browser-based.

How it works

  1. Upload WebM Files — Drag and drop your WebM files into the converter, or click to browse. Common sources: youtube (internal format), web applications.
  2. Convert to MKV — The converter processes your files to MKV format entirely in your browser. No files are uploaded to any server — your privacy is guaranteed.
  3. Download Results — Download your converted MKV files instantly. For multiple files, download individually or as a ZIP archive.

Why convert WEBM to MKV

  • Convert to lossless MKV format to prevent further quality degradation during editing
  • Leverage MKV advantages: supports multiple audio/subtitle tracks
  • Overcome WebM limitations: no safari support on older versions
  • Upload to websites and platforms that require or prefer MKV format

FAQ

Is WebM to MKV conversion free?
Yes, Fileza.io converts WebM to MKV completely free with no limits on file size or number of conversions. No hidden fees, no watermarks, and no account required.

Will I lose quality converting WebM to MKV?
Both WebM and MKV use lossy compression. Output quality is excellent at high quality settings (85%+) — most people cannot see any difference.

Is it safe to convert WebM to MKV online?
Absolutely. Unlike most online converters, Fileza.io processes your files entirely in your browser using WebAssembly. Your WebM files are never uploaded to any server — the conversion runs on your own device, keeping your files 100% private.

Can I convert multiple WebM files to MKV at once?
Yes, Fileza.io supports batch conversion. Drag and drop multiple WebM files at once and they will all be converted to MKV simultaneously. Download them individually or as a ZIP archive.

Does WebM to MKV conversion work on mobile?
Yes, the converter works on any device with a modern web browser — iPhones, iPads, Android phones, and tablets. No app installation required.

Will the converted MKV files be smaller or larger than WebM?
File sizes depend on content and quality settings. WebM files are typically small (vp9/av1 codec), while MKV files are varies by codec.

How long does WebM to MKV conversion take?
Most conversions complete in seconds. The exact time depends on file size and your device performance. Since processing happens locally in your browser, faster devices convert more quickly. Video files may take longer due to re-encoding.