Convert MP4 to MKV

Free online MP4 to MKV converter. No signup required.

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Max file size: 100 MB

When to convert MP4 to MKV

Use this conversion when your destination needs MKV and you have a MP4 source. Keep the original so you can compare the result or try another supported format.

Video is re-encoded using the selected output’s defaults. Image quality, audio and metadata can change. Check playback and duration in the application where you will use it.

MP4 vs MKV: Format Comparison

Side-by-side comparison of the source and target formats.

PropertyMP4 (Source)MKV (Target)
Extension.mp4.mkv
Full NameMP4 VideoMatroska Video
CompressionLossyLossy
File SizeMediumMedium
Best ForWeb video streaming on YouTube, Vimeo, and so…High-definition movie and TV show storage wit…
Browser SupportUniversalWide

How to Convert MP4 to MKV

Follow these simple steps to convert your file in seconds.

  1. Choose a MP4 file

    Select or drop one file up to 100 MB. Its extension must match this converter. Availability is checked before transfer.

  2. Convert to MKV

    Video is re-encoded using the selected output’s defaults. Image quality, audio and metadata can change. Check playback and duration in the application where you will use it.

  3. Download and check the result

    Use Download after conversion completes. Open the result and check its content, quality and formatting before sharing it. Download links expire one hour after upload finishes. Uploaded and converted files are removed automatically by regular cleanup. Files may become unavailable sooner when the service restarts.

Tips for Converting MP4 to MKV

Practical advice to get the best results from this conversion.

Why this conversion is worth doing

MP4 Video has a known limitation: patent-encumbered codecs (H.264/H.265) require licensing. Matroska Video addresses this with a key advantage: supports virtually any codec and unlimited tracks for audio, subtitles, and video. Converting from MP4 to MKV is most worthwhile when this specific trade-off matters for the way you intend to use the file.

Match the format to the actual workflow

MP4 Video is most commonly used for web video streaming on youtube, vimeo, and social media, while Matroska Video is the standard for high-definition movie and tv show storage with multiple audio and subtitle tracks. If your workflow is closer to the second pattern, converting makes sense. If you are still working in a context where MP4 is the norm, converting may create unnecessary compatibility friction with collaborators or tools that expect the source format.

Watch for this limitation in the MKV output

Matroska Video has its own limitation worth understanding before you commit: not natively supported by all hardware devices and smart TVs. After the conversion completes, open the MKV file and verify that this limitation does not affect your specific use case — for some workflows it is irrelevant; for others it can be a deal-breaker.

Avoid transcoding unless necessary

Every time you transcode (re-encode) a video, some quality is lost unless you use a lossless codec. If you only need to change the container format without changing the codec, use a remux (stream copy) operation instead of a full re-encode. This preserves original quality and is much faster.

Understanding MP4 and MKV Formats

Learn about the source and target file formats to understand what happens during conversion.

Source Format

MP4 Video

video/mp4

MP4 (MPEG-4 Part 14) is the most widely used digital video container format, capable of storing video, audio, subtitles, and metadata. It typically contains H.264 or H.265 encoded video with AAC audio, providing an excellent balance of quality and compression. MP4 is the standard format for web video, streaming, and virtually all modern video platforms.

Advantages

  • Universal compatibility across all devices, browsers, and platforms
  • Excellent compression with H.264/H.265 codecs for high-quality video
  • Supports streaming, subtitles, chapters, and multiple audio tracks

Limitations

  • Patent-encumbered codecs (H.264/H.265) require licensing
  • Container flexibility can lead to codec compatibility issues
  • Not ideal for lossless video storage or professional editing

Common Uses

  • Web video streaming on YouTube, Vimeo, and social media
  • Smartphone and camera video recording
  • Digital video distribution and download

Target Format

Matroska Video

video/x-matroska

MKV (Matroska Video) is a free, open-standard multimedia container that can hold an unlimited number of video, audio, subtitle, and metadata tracks in a single file. It supports virtually any codec and is especially popular for high-definition video content with multiple audio and subtitle options. Matroska is designed to be future-proof with a flexible, extensible EBML-based structure.

Advantages

  • Supports virtually any codec and unlimited tracks for audio, subtitles, and video
  • Rich feature set including chapters, menus, metadata, and attachments
  • Open standard that is free and widely supported by media players

Limitations

  • Not natively supported by all hardware devices and smart TVs
  • Larger overhead compared to simpler containers like MP4
  • Not supported for direct playback in most web browsers

Common Uses

  • High-definition movie and TV show storage with multiple audio and subtitle tracks
  • Anime and media collections requiring multiple language options
  • Video archival with comprehensive metadata preservation

Frequently Asked Questions

Common questions about converting MP4 to MKV.

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