CLZ File

What are CLZ files and how to open them

Are you having problems opening a CLZ file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CLZ files.

What is a CLZ file?

A .CLZ file is a ChiefLZA Compressed Archive file.

ChiefLZA Compressed Archive files store a single compressed data stream created by the ChiefLZ library, a Pascal-based compression library developed by Dr Abimbola Olowofoyeku (also known as "The African Chief") from about 1996 onward. These archives are used when a program or installer wants to compress one file or data blob rather than bundle multiple files into a multi-file archive. ChiefLZ also supports related formats: the LZA format, which adds archiving of multiple files (with features like password protection, splitting into volumes, or self-extracting archives), and the single-stream LZZ format.

A ChiefLZA Compressed Archive is produced by the ChiefLZ library in the LZA mode after archiving file member(s), then compressing that archive. To use it, software typically reads and decompresses the data stream inside to recover the archived files. ChiefLZA files are lossless, preserving every bit of the original data. Compression is based on a custom Lempel - Ziv method; exact algorithmic details vary depending on mode (faster or more compact) selected in ChiefLZ. Tools created by the community (such as "CLZ-Compression" on GitHub) implement both decompression and recompression consistent with observed headers and compression codes.

Files begin with a 16-byte header. The signature at offset zero is the ASCII sequence ChfLZ, encoded as bytes 43 66 68 4C 5A, followed by a zero byte. At offsets 4 and 12 two identical 32-bit big-endian integers record the size of the uncompressed data. Bytes 8-11 are zero. After the header, compressed bytes follow, mixing raw bytes and back-references: distance/length codes referencing a 4096-byte sliding window. When a control bit is zero, a raw byte is read; when one, a two-byte distance/length code is read, with length equal to the lower nibble plus three, and distance encoded combining bits from both bytes.

How to open CLZ files

Important: Different programs may use files with the CLZ file extension for different purposes, so unless you are sure which format your CLZ file is, you may need to try a few different programs.

While we have not verified the app ourselves yet, our users have suggested a single CLZ opener which you will find listed below.

Last updated: August 31, 2026

Various apps that use files with this extension

These apps are known to open certain types of CLZ files. Remember, different programs may use CLZ files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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