FILE FORMAT GUIDE
GZ File: What It Is & How to Open It
A GZ file contains one or more gzip members. Each member has a header, Deflate-compressed data and a trailer with CRC-32 and uncompressed size information.
Compare the reviewed GZIP header signature with the filename in your browser.
Check supported file headersQuick facts
- Extension
- .gz
- Format
- GZIP Compressed File
- Category
- archive
- MIME type
- application/gzip
- Standard / developer
- IETF
- Open with
- 7-Zip, Archive Utility
What is GZ?
The fixed 1F 8B bytes identify gzip and the method byte normally selects Deflate. Member concatenation is part of the format; the original filename and timestamp are optional metadata, not guaranteed facts.
How to open GZ
7-ZipWindows
Right-click the .gz file, choose 7-Zip, and extract it to a separate folder. A .gz file usually contains one compressed file rather than a folder tree.
Archive UtilitymacOS
Double-click the .gz file in Finder to expand it beside the original archive.
Common uses and compatibility
- Compress a byte stream for storage or transfer
Things to check
- Gzip does not provide random access, archive directory semantics or encryption.
Technical details
- Signature
- 1F 8B
- Encoding
- Not reviewed
- Container
- Series of gzip members
- Compression
- Deflate
Related formats
- Debian Binary Package
A Debian package may contain gzip-compressed members inside its outer ar archive.
Sources & review
Sources reviewed 2026-09-19.