MKV to MP4

Convert an MKV or WebM video to widely-supported MP4 — keeps quality intact whenever a fast remux is possible.

FreeUp to 100MBMP4 output

Drop an MKV or WebM file here or click to browse

Matroska .mkv or .webm files — up to 100MB

How it works

A compact workflow from input to download.

Upload your MKV or WebM file

Choose a .mkv or .webm video up to 100MB.

We convert it

The file is remuxed to MP4 instantly, or transcoded if the codec needs it.

Download the MP4

Get a video file that plays on any device or platform.

Frequently asked questions

Why convert MKV to MP4?

MKV is a flexible container but has patchy support on phones, TVs, and older software. MP4 plays almost everywhere.

Will converting reduce quality?

When the video's codec is already compatible, we simply repackage the file (remux) with no quality loss. Otherwise we transcode, which is visually near-identical.

What's the maximum file size?

Uploads are capped at 100MB.

Is my video stored anywhere?

No. The file is processed and deleted immediately after your download completes.

Will I lose subtitles or extra audio tracks?

Possibly. MKV can hold multiple audio tracks, embedded subtitles, and chapters that MP4 supports more narrowly. A basic conversion keeps the main video and audio; secondary tracks and soft subtitles may be dropped. If you need every track preserved, keep the MKV or mux subtitles separately.

How long does the conversion take?

If the codecs are already MP4-compatible, a remux finishes in seconds because no video is re-encoded. If a transcode is required (for example, an unusual codec), it takes longer because every frame is decoded and re-encoded.

MKV to MP4: Remuxing vs. Re-encoding

MKV (Matroska) and MP4 are both containers— formats that bundle a video stream, one or more audio streams, and extras like subtitles and chapters into a single file. MKV is the more flexible of the two: it can hold almost any codec and an unlimited number of tracks, which is why it is popular for archived films and high-quality rips. MP4 is more restrictive, but that restriction is exactly why it plays reliably on phones, smart TVs, browsers, and social platforms where MKV often fails. Converting from one to the other can happen in two very different ways, and knowing which one you are getting explains the speed and quality you see.

Remuxing: fast and lossless

If the video inside your MKV is already encoded with a codec MP4 supports — most commonly H.264 or H.265/HEVC— then no re-encoding is needed. The streams are simply copied out of the MKV wrapper and placed into an MP4 wrapper, a process called remuxing. Because not a single frame is re-compressed, the result is bit-for-bit identical in quality to the source and completes almost instantly. This is the ideal path and the one this tool takes whenever the codec allows it.

Re-encoding: slower, slight quality cost

Some MKV files use codecs MP4 does not officially support — for example, older VP8/VP9 video or certain lossless audio formats. In those cases the video has to be transcoded: decoded frame by frame and re-encoded to an MP4-friendly codec. Transcoding takes real processing time and, because H.264/H.265 are lossy, introduces a small quality reduction. In practice a well-configured transcode is visually near-identical to the original, but it is worth knowing why a conversion sometimes takes minutes instead of seconds.

What can get left behind

Because MKV can carry things MP4 handles less gracefully, a conversion may simplify your file. Multiple audio tracks (say, several dubbed languages), embedded soft subtitles, and chapter markers are the usual casualties. If you only care about the main picture and sound, this is a non-issue. If you need every track intact, either keep the original MKV or export the subtitle and audio tracks separately before converting.

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