Convert MKV to MP4.
Make Matroska .mkv videos play everywhere as MP4 — fast remux with ffmpeg, quality preserved.
MKV vs MP4
MKV (Matroska) is a flexible open container — it can hold almost any codec along with multiple audio and subtitle tracks, which is why movie rips so often use it. MP4 is the universal one that just plays: on phones, smart TVs, the web and in every video editor. Plenty of devices simply won't open an MKV, and converting fixes that.
Usually a fast, lossless remux
Most MKVs already hold H.264 or H.265 video, which MP4 also supports — so the streams are copied into a new MP4 container without re-encoding. That's quick and loses no quality. Only a codec MP4 can't carry would force a high-quality re-encode.
Watch the extra tracks
The one thing to know: MKV can bundle several audio languages and subtitle tracks, and MP4 handles fewer. Extra tracks may be dropped or need picking, and embedded subtitles in particular often don't carry across — keep the MKV if those matter to you.
How it works
- 01
Add your MKV
Drop one or many files, or click to browse. Private by default.
- 02
Convert with a local engine
MKV becomes MP4 using a best-in-class open engine — no paid API in the loop.
- 03
Download
Grab your MP4 (or a zip of many), or open it in TranscriptAI to do more.
Best available engine, honest about limits
Private uploads, auto-deleted after 1 hour
Batch convert many at once, download as a zip
No watermark, no signup to try
Fast, faithful conversion
Direct handoff to TranscriptAI
MKV to MP4: transcode
MKV and MP4 are container/codec formats, so this re-encodes the video (a lossy step — start from the best source you have). MP4 is broadly compatible, which helps when a player, editor or site won't accept MKV.
Your file is ready. Want to do more with it?
Open this file in TranscriptAI to generate a transcript, summary, structured notes, flashcards, quiz questions or action items — automatically.
Common questions
Is it free?+
Yes — convert MKV to MP4 free, with no signup.
Is my file private?+
Uploads go to a private bucket, are converted, and auto-delete after 1 hour.
Will quality hold up?+
Remuxed without re-encoding where possible.
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