🎬 Video Converter
Convert WebM to MKV — Free & Private
Convert WebM to MKV to store web video in a flexible container with multi-track support.
✓ Free forever✓ No upload✓ No signup✓ Instant
Ready to convert your WebM?
100% in your browser · Powered by FFmpeg.wasm · No account needed
How to Convert WebM to MKV
1
Open the Converter
Click "Convert Now" to open with WebM → MKV pre-selected.
2
Upload Your WebM
Drag & drop your WebM file or click Browse to select it.
3
Convert Instantly
FFmpeg.wasm processes your video locally — nothing uploaded.
4
Download MKV
Your converted MKV file downloads automatically when ready.
Why Convert WebM to MKV?
- 🌐 From WebM — convert web-optimised WebM video to formats compatible with desktop apps
- 📦 Flexible container — MKV supports multiple audio tracks, subtitles, and chapters
- ✨ Quality preserved — video stream copied without re-encoding where possible
- 🌍 Open standard — supported by VLC, Plex, Kodi, and most modern players
- 🔊 Multi-track audio — store multiple language tracks in a single file
- 🔒 100% private — files never leave your device
Features
100% Private
Files never leave your browser. Powered by FFmpeg.wasm.
Instant
In-browser processing — no server queue, no waiting.
Free
No account, no fee, no watermarks. Ever.
Quality Preserved
Converts at the highest quality settings by default.
Mobile-Friendly
Works on any device — phone, tablet, desktop.
No Install
Nothing to download. Works in any modern browser.
Frequently Asked Questions
Yes — 100% free, no limits, no watermarks, no account needed.
No. All conversion happens locally using FFmpeg.wasm. Your files never leave your device.
Quality depends on the target format. Conversions use high-quality settings by default.
Yes — there is no strict size limit, though very large files may take longer on slower devices.
Speed depends on file size and your device. FFmpeg.wasm processes everything locally in your browser.