What is the Maximum MKV File Size Limit?

This article explores the maximum file size limit for the MKV (Matroska) container format. While the MKV specification allows for virtually unlimited file sizes, practical limits are almost always dictated by the file system of the storage device being used rather than the container format itself.

The Theoretical MKV File Size Limit

The Matroska (MKV) container is built on EBML (Extensible Binary Meta Language), which is a binary, XML-like format. In the EBML specification, data sizes are defined using variable-length descriptors that can be up to 8 bytes long.

This 8-byte limit allows the MKV container to theoretically support file sizes up to 2^56 - 2 bytes, which is approximately 72 petabytes (72,000 terabytes). For all practical purposes in modern computing and video production, this theoretical limit is considered infinite.

Practical Limits Imposed by File Systems

Since the MKV format itself does not impose a restrictive limit, the actual maximum size of an MKV file you can create or store depends entirely on the file system of the storage drive you are using.

• FAT32: If you are storing an MKV file on a drive formatted with FAT32, the maximum file size is strictly limited to 4 GB. Trying to transfer an MKV file larger than this will result in a “file too large” error.
• NTFS: The default file system for Windows supports a maximum file size of 16 TB to 256 TB (depending on the specific Windows implementation), which easily accommodates any MKV video.
• exFAT: Commonly used for cross-compatibility between Windows and Mac, exFAT supports a maximum file size of 16 EB (Exabytes).
• ext4: The standard Linux file system supports individual file sizes up to 16 TB.
• APFS: Apple’s file system supports file sizes up to 8 EB.

Conclusion

You do not need to worry about the limitations of the MKV container itself when encoding, muxing, or downloading high-definition video files. If you encounter a file size limitation error when handling an MKV file, the issue is caused by a restrictive storage file system like FAT32, which can be resolved by reformatting the storage drive to a modern file system like exFAT or NTFS.