Video
Convert MKV to MP4 Online — Free
MKV is a great container but unsupported in most browsers, iPhones, and TVs. ReFile remuxes MKV to MP4 — same video and audio bytes, new container — so playback works everywhere without re-encoding.
- No signup to try
- Sandboxed processing
- Files deleted in 24 h
What this does
- Lossless container swap (fastest)
- Pick one audio track if your MKV has several — 'keep the English track only'
- Strip subtitles or burn them in — 'burn the English subs into the video'
How it works
- 1
Upload your MKV
Drop it above, or click to pick from your device. We validate the format immediately — no spinning on a file we can't process.
- 2
Run the conversion
The recipe runs in an isolated cloud sandbox — same as every other ReFile job. No AI guessing involved; it's a hand-written command that does one thing.
- 3
Download the MP4
Result lands in seconds. Files auto-delete from our servers after 24 hours; signed download URLs expire in the same window.
Frequently asked
- Does this re-encode?
- Not by default — codec copy is the fastest and lossless path. ReFile only re-encodes if your MKV uses a codec that MP4 doesn't support (rare), or if you ask for a specific bitrate or resolution.
- What about multiple audio tracks?
- Ask in plain language: 'keep only the English audio', 'use the second audio track'. ReFile picks the right FFmpeg map flags for you.