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MKV to MP4 Converter — Free, Fast, No Upload

MKV videos from downloads, OBS or screen recorders won't play on an iPhone or upload to many sites. Repackage them as MP4 here — H.264 and HEVC video isn't re-encoded.

Free · no signup2 free files a day100% in-browser · no uploadPopular converter

Tap to select MKV files

or click to browse

2 free files per day (2 left today) · Up to 10 MB each · Upgrade for more

✓ Files never uploaded✓ 100% browser-based✓ No account required
Need the reverse?MP4 → MKV

How to convert MKV to MP4 online

  1. 1

    Drop your MKV file

    Drag your Matroska Video file onto the box above, or click it to pick a file.

  2. 2

    Wait while it converts

    Conversion starts on its own and runs on your device, not on a server. Video takes roughly as long as the clip plays, so keep the tab open.

  3. 3

    Download your MP4

    Click Download to save the MPEG-4 Part 14 file.

MKV vs MP4: format overview

MKV

Matroska Video

Matroska.org · 2002

Compression
lossy
Transparency
No
  • ✓ Supports virtually any codec combination
  • ✓ Multiple audio tracks and subtitles per file
  • ✗ Not natively supported by iOS or older devices
MP4

MPEG-4 Part 14

Moving Picture Experts Group · 2001

Compression
lossy
Transparency
No
  • ✓ Universal compatibility across all platforms
  • ✓ Excellent compression with H.264/H.265

MKV magic bytes: 1A 45 DF A3

MP4 magic bytes: 00 00 00 xx 66 74 79 70

Why convert MKV to MP4?

MKV (Matroska) is a flexible video container. One file can hold several audio tracks, subtitles and chapters, which is why downloaded videos and OBS recordings often use it. The catch is support: iPhones, iPads and QuickTime on a Mac don't open MKV, and many editors and upload forms ask for MP4 instead.

MP4 is the format almost every phone, browser, editor and website accepts.

Most MKV files hold H.264 or HEVC video, which MP4 can carry as it is. So this converter doesn't rebuild the picture — it copies the video into an MP4 wrapper. That's fast, and the picture doesn't change. Other video, such as VP9 or AV1, is re-encoded to H.264 so the MP4 plays everywhere.

Common reasons to convert MKV to MP4:

  • ›Playing a video on an iPhone, iPad or Mac
  • ›Editing in an app that doesn't import MKV
  • ›Uploading to a site that only lists MP4
  • ›Sharing an OBS or screen recording with someone else

Quality & file size: MKV to MP4

H.264 and HEVC video is not re-encoded. The video stream is copied into the MP4 as it is, so resolution, frame rate and sharpness stay the same.

AAC sound is copied as it is. Other sound, such as AC-3, DTS, Opus or Vorbis, is re-encoded to AAC at 192 kbps, the standard audio for MP4. Stereo stays stereo and surround stays surround.

The MP4 gets one video track and one audio track. Following FFmpeg's rules, the audio with the most channels is picked — on a file with several languages that may not be the one you want. Picture-based subtitles, such as PGS from Blu-ray or VobSub from DVD, are left out. Keep the MKV if you need every track.

Other video codecs, such as VP9, AV1 or the MPEG-4 video of old Xvid files, are re-encoded to H.264 instead, so the MP4 plays on iPhones and in every browser. That takes much longer, and the picture is compressed once more.

Frequently asked questions

Does converting MKV to MP4 reduce quality?
Not for H.264 or HEVC video, which is copied without re-encoding. AAC sound is copied too; other sound is re-encoded to AAC at 192 kbps.
How do I convert MKV to MP4 without re-encoding?
That's how this page works when the video is H.264 or HEVC, as it is in most MKV files: the video is copied, never re-encoded, and AAC sound is copied too. Other codecs are re-encoded to H.264 and AAC.
Will subtitles be kept?
Don't count on it. Picture-based subtitles, such as PGS from Blu-ray or VobSub from DVD, are always left out. Keep the MKV if you need subtitles.
My MKV has several audio tracks — which one do I get?
One: the track with the most channels, so a 5.1 track wins over a stereo one. If you need a different language, a desktop app lets you pick tracks.
Can I convert a whole movie?
Only if it's small enough. The free tier takes files up to 10 MB and Pro up to 500 MB. Full-length movies are usually several gigabytes, so use a desktop app for those.
I recorded in OBS — how do I get an MP4?
OBS can do it itself: choose File > Remux Recordings, or turn on automatic remux to MP4 in Settings > Advanced. This page also works for recordings up to 500 MB with Pro.
How do I convert MKV to MP4 on a Mac?
QuickTime can't open MKV, but this page works in Safari or Chrome: drop the MKV and download the MP4. Nothing to install.
What happens to VP9 or AV1 video?
It is re-encoded to H.264, which every phone and browser plays. That takes much longer than a copy, and the picture is compressed once more, so fine detail can soften slightly.
Is MKV better than MP4?
They're both containers, so the picture quality depends on what's inside, not the wrapper. MKV can hold more — several audio tracks, many subtitle types and chapters in one file. MP4 plays on far more phones, apps and websites. That's why people keep MKV for archives and use MP4 for sharing.

Your MKV file never leaves this tab — FormatDrop has no endpoint that receives file data. How it works