What is ZIP?
ZIP is an archive file format that supports lossless data compression. A ZIP file contains one or more files that have been compressed to reduce file size, making it easier to store and transfer multiple files as a single package.
The format uses various compression algorithms, with DEFLATE being the most common. ZIP files can also store files without compression and support password protection and encryption.
Features
- Lossless compression
- Multiple files in single archive
- Password protection and encryption
- Split archives (multi-volume)
- File comments and metadata
- Directory structure preservation
- Selective file extraction
- No file size limits (ZIP64)
- Universal compatibility
Use Cases
Perfect For
- Email attachments with multiple files
- Software distribution and downloads
- Document archival and backup
- File transfers over the internet
- Reducing storage space
- Organizing project files
- Sharing photo collections
Advantages
- Universal compatibility (all platforms)
- Built-in support on major operating systems
- Good compression ratios
- Fast compression and decompression
- Password protection available
- Supports very large files (ZIP64)
- Can extract individual files
- Open specification
Disadvantages
- Compression efficiency: Not as efficient as 7z or RAR
- No error recovery: Corrupted archives can't be repaired
- Weak encryption: Standard ZIP encryption is easily broken
- No solid compression: Compresses files individually
Technical Information
ZIP files use a directory structure at the end of the archive, allowing quick file browsing without decompressing. The DEFLATE algorithm is most commonly used, combining LZ77 and Huffman coding for efficient compression.
| File extension | .zip |
| MIME type | application/zip |
| Compression | DEFLATE, BZIP2, LZMA, others |
| Max file size | 16 exabytes (ZIP64) |
| Encryption | ZipCrypto, AES-128, AES-256 |
Compression Levels
- Store (0): No compression
- Fastest (1-3): Quick but larger files
- Normal (5-6): Good balance
- Maximum (9): Best compression, slower