What is the ZIPX file format?
.zipx is an archive file format that uses advanced compression algorithms, offering higher compression ratios and compression times than the classic ZIP format. Each .zipx archive contains a header section holding metadata and information about the compression method used for each entry. Unlike standard .zip, .zipx entries use compression method IDs beyond DEFLATE (method 8): BZip2 (method 12), LZMA (method 14), PPMd (method 98), and XZ/LZMA2 (method 95), among others.
.zipx format is not as popular as .zip. Archives in this format require Corel WinZip version 12.1 or greater, or a compatible tool such as 7-Zip (9.20+) or PeaZip. Although ZIPX was introduced in 2009, it never became a popular standard; standard unzip utilities fail on entries using non-DEFLATE methods.
Technically, .zipx is not a separate binary format - it is standard ZIP with a distinct extension, coined by WinZip to signal the need for extended-method decoding. LZMA and XZ typically yield 5-20% better ratios than DEFLATE; PPMd excels on text. AES-256 encryption and ZIP64 extensions (for files over 4 GB) are both supported.
Security & safety
RISK: MEDIUMSame risk profile as ZIP archives: contents can include malware, and advanced compression methods (LZMA, PPMd) may be used to create zip-bomb-style decompression attacks with extreme expansion ratios. Always scan ZIPX files from unknown sources with antivirus before extracting. Tools like 7-Zip and PeaZip have built-in decompression limits to mitigate zip-bomb attacks.
Format details
in a nutshellPrograms that open ZIPX files
Windows3 apps
7-Zip
Open-source Right-click → 7-Zip → Extract Here (or Extract to folder). Supports BZip2 and LZMA methods; PPMd/XZ support added in recent versions. 
macOS3 apps
The Unarchiver
Free Double-click the ZIPX file; The Unarchiver extracts supported ZIPX methods automatically. 
Linux2 apps
PeaZip
Open-source Right-click → PeaZip → Extract here, or use command line: peazip -ext2here file.zipx 
Android1 app
Technical details
deep spec| Developer | Corel Corporation (WinZip division) |
| Introduced | November 2009, WinZip 12.1 |
| Base structure | Standard ZIP (PKWARE APPNOTE-compatible central directory and local file headers) |
| Magic bytes | PK\x03\x04 (50 4B 03 04) - identical to .zip; distinction is in per-entry compression method IDs |
| Supported compression methods | BZip2 (method 12), LZMA (method 14), PPMd (method 98), XZ/LZMA2 (method 95), JPEG (method 96), WavPack (method 97) |
| Encryption | AES-256 (WinZip AES scheme; identical to .zip strong encryption) |
| Checksum integrity | CRC-32 per entry; AES-based MAC when AES encryption is active |
| Maximum entries | 65,535 (ZIP limit); ZIP64 extension removes this cap |
| Compression improvement | LZMA and XZ typically yield 5-20% better ratios than DEFLATE; PPMd gives best results for text |
| Minimum compatible tools | WinZip 12.1+, 7-Zip 9.20+, PeaZip, The Unarchiver |
| File size limit | ZIP64 extension allows archives and individual entries exceeding 4 GB |
| Standard compatibility | PKWARE APPNOTE-compliant structure; standard unzip tools fail on entries using non-DEFLATE methods |
| Released | 2009 (WinZip 12.1) |
| Latest version | WinZip 28 (2024); XZ compression added in WinZip 18 |
| Open standard | Yes · royalty-free |
| Specification | support.winzip.com |
ZIPX conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about ZIPX files.
