MP4 to MKV Converter

Convert MP4 video files to Matroska MKV online for free. Perfect for Plex, Kodi, and media libraries. No software needed. Up to 100 MB.

256-bit SSL 500K+ conversions 4.9 rating Files auto-deleted in 2h

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Also supports MKV, MOV, AVI, WebM, WMV, FLV • Max 100 MB

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How to Convert MP4 to MKV

1

Upload

Drag and drop your MP4 video into the converter above, or click Choose MP4 File to browse your device.

2

Convert

Click Convert to MKV. Our server repackages your video into the Matroska container. Takes under a minute for most files.

3

Download

Click Download MKV to save the converted video. That's it — no registration, no email required.

Why MKV for Your Media Library

Plex & Jellyfin Media Servers

MKV is the preferred container for Plex, Jellyfin, and Emby media servers. It allows you to embed multiple audio tracks (English, Spanish, commentary), subtitle files (SRT, SSA/ASS, PGS), and chapter markers — all in a single file. Media servers can read these tracks and let viewers switch between them during playback without needing separate files.

Kodi & Home Theater PCs

Kodi has full native MKV support and leverages every feature of the Matroska container: chapter navigation, multiple audio streams, embedded subtitles with styling (ASS/SSA), and rich metadata including cover art and tags. For HTPC setups, MKV gives you the most complete viewing experience with all tracks and metadata in one file.

Multiple Audio Tracks

MP4 has limited multi-track support, while MKV handles unlimited audio streams in any format — AAC, FLAC, DTS, Dolby TrueHD, Opus, and more. This is essential for multilingual content, director's commentary, and audiophile-grade lossless audio tracks. You can store every audio version in a single file instead of managing multiple copies.

Archival & Preservation

MKV is the industry standard for video archiving. Its open-source format ensures long-term accessibility without licensing concerns. Unlike MP4, MKV can store lossless video (FFV1) and lossless audio (FLAC) with full metadata, chapter markers, and attachments like fonts for styled subtitles. Libraries and archivists worldwide rely on MKV for preservation.

What is MP4?

MP4 (MPEG-4 Part 14) is the international standard video container format, published as ISO/IEC 14496-14. Derived from Apple's QuickTime MOV format in 2001, it uses an atom/box architecture for organizing video, audio, and metadata streams.

MP4 primarily supports H.264 and H.265 video with AAC audio, and includes the faststart flag (moov atom at the beginning) for instant web playback. It's the recommended upload format for YouTube, Instagram, TikTok, Facebook, and every major platform.

The defining strength of MP4 is universal compatibility. Every computer, phone, tablet, smart TV, gaming console, and web browser manufactured in the last 15 years plays H.264 MP4 natively. However, MP4 has limited track support — it struggles with multiple audio tracks, advanced subtitles, and chapter metadata compared to MKV.

What is MKV?

MKV (Matroska Video) is an open-source, free container format created in 2002 by Steve Lhomme. Named after Russian Matryoshka nesting dolls, it was designed to hold virtually anything: unlimited video, audio, subtitle, and chapter tracks in a single file.

MKV supports every major video codec — H.264, H.265, VP9, AV1, FFV1, MPEG-4 — along with audio codecs like AAC, FLAC, DTS, Dolby TrueHD, Opus, and PCM. It can embed SRT, SSA/ASS, and PGS subtitles, chapter markers for scene navigation, attachments like fonts, and rich metadata including cover art.

MKV is the standard container for media libraries. Software like Plex, Kodi, Jellyfin, and VLC handles MKV perfectly. Its open-source license (LGPL) means no royalty concerns and guaranteed long-term format support. MKV is the go-to format when you need flexibility, archival quality, and full metadata support.

MP4 vs MKV: Quick Comparison

Feature MP4 MKV
Developer ISO/MPEG (2001) Matroska.org (2002)
License ISO standard (patented codecs) Open source (LGPL)
Video codecs H.264, H.265, AV1 H.264, H.265, VP9, AV1, FFV1, virtually any
Audio codecs AAC, MP3, AC-3 AAC, FLAC, DTS, TrueHD, Opus, AC-3, PCM
Subtitle support Limited (tx3g text only) SRT, SSA/ASS, PGS, VobSub (unlimited tracks)
Multiple audio tracks Supported (limited) Unlimited
Chapter markers Basic support Full support with nested chapters
Attachments (fonts, etc.) Not supported Full support
Lossless codecs Limited FFV1, FLAC, PCM — full support
Device compatibility Universal (all devices) Media servers, VLC, desktop players
Web browser playback All browsers (H.264) Not supported
Best for Sharing, web, universal playback Media libraries, archiving, Plex/Kodi

Why Convert MP4 to MKV?

Media server organization

Plex, Jellyfin, Kodi, and Emby all work best with MKV files. The Matroska container lets media servers properly index multiple audio tracks, subtitle streams, and chapter markers. If you're building a home media library, standardizing on MKV gives you the most organized and feature-complete collection with full metadata support.

Multiple audio tracks

MP4 has limited multi-audio support, and many players struggle with MP4 files containing more than one audio stream. MKV handles unlimited audio tracks natively — store English 5.1, Spanish stereo, director's commentary, and lossless FLAC all in a single file. Every major media player can switch between MKV audio tracks seamlessly.

Subtitle embedding

MP4 only supports basic tx3g text subtitles. MKV supports SRT, SSA/ASS (with full styling, fonts, and positioning), PGS (Blu-ray image subtitles), and VobSub (DVD subtitles). If you need styled subtitles, karaoke effects, or Blu-ray-quality image-based subs, MKV is the only mainstream container that handles them all.

Archival & future-proofing

MKV's open-source license (LGPL) guarantees the format will remain freely accessible forever — no licensing fees, no patent expirations, no corporate discontinuation. It supports lossless codecs (FFV1 for video, FLAC for audio) for true archival quality. Major institutions and the digital preservation community have adopted MKV as a standard archival container.

Frequently Asked Questions

No. Converting MP4 to MKV is typically a remux — the video and audio streams are copied directly into the Matroska container without re-encoding. This means zero quality loss. The MKV file contains the exact same H.264 video and AAC audio data as the original MP4, just in a different container.
MKV is the preferred format for media servers like Plex, Jellyfin, and Kodi because it supports unlimited audio tracks (multiple languages), advanced subtitle formats (SRT, SSA/ASS, PGS), chapter markers for scene navigation, and virtually any codec. If you're building a media library or need to embed multiple audio and subtitle tracks, MKV is the standard container.
MP4 is the ISO standard container optimized for universal device compatibility — it works on every phone, TV, and browser. MKV (Matroska) is an open-source container designed for flexibility — it supports unlimited audio, subtitle, and chapter tracks with virtually any codec. MP4 is best for sharing and streaming; MKV is best for media libraries, archiving, and multi-track content.
Yes. MKV supports an unlimited number of audio tracks in any format — AAC, FLAC, DTS, Dolby TrueHD, Opus, AC-3, and more. This is one of the main reasons media enthusiasts prefer MKV over MP4. You can store English, Spanish, Japanese, and commentary audio tracks all in a single file, and switch between them during playback.
Yes. Plex, Kodi, Jellyfin, Emby, and virtually every media server software has excellent MKV support. MKV is the de facto standard container for home media libraries. These servers can read multiple audio tracks, embedded subtitles, chapter markers, and metadata from MKV files without any issues.
Since MP4 to MKV is typically a remux (no re-encoding), the conversion is very fast — usually under 30 seconds for most files. The process simply repackages the existing video and audio streams into an MKV container without touching the actual media data. Processing happens on our server, so your device speed does not affect conversion time.
Yes. Convertio.com offers free MP4 to MKV conversion with no watermarks, no registration, and no email required. Upload your file, convert, and download. Your files are encrypted during transfer and automatically deleted from our servers within 2 hours.

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