Free online MP4 Video to Matroska Video converter. Files are processed locally in your browser — no uploads, 100% private.
Drop your .MP4 file here
or click to browse from your device
100% browser-based — no server uploads, no cloud processing
Free forever — no account or subscription required
Supports batch conversion for multiple files at once
Works on any device — desktop, tablet, and mobile
Results available in seconds — no server queue or wait time
Files are cleared immediately after processing for maximum privacy
H.264/MPEG-4 — the universal video container standard
Open multimedia container supporting all codecs
MKV is an industry-standard format with universal support
Source: H.264/MPEG-4 — the universal video container standard
Output: Open multimedia container supporting all codecs
100% browser-based processing — files never leave your device
Re-encoding causes quality loss
H.264 may require licensing fees in some commercial contexts
Large file sizes for high-resolution or long content
Online video hosting and social media uploads
Video editing projects and source files
Streaming and progressive web video delivery
Long-term video archiving
Use H.264 with CRF 18–23 for an excellent quality-to-size ratio
Set audio to AAC 128 kbps for most content; 192 kbps for music
Add the -movflags faststart flag to enable web streaming from the start
H.265 achieves 40–50% better compression but has broader compatibility issues
Drag & drop your file or click to browse
Files are processed instantly in your browser
Save your converted or processed file
Upload your MP4 file using the drop zone above. Your file is instantly converted to MKV format right in your browser — no server upload, no waiting.
Completely. Our converter processes your MP4 file 100% in your browser using client-side code. It never leaves your device or touches any external server.
It depends on the formats. Converting from lossless to lossy (e.g. PNG to JPEG) may reduce quality. Converting lossless-to-lossless (e.g. PNG to WebP lossless) preserves all quality.
Free, instant, and 100% private. Your files are processed locally in your browser.