File compression reduces storage needs and speeds up transfers. But with dozens of formats and tools available, choosing the right approach can be confusing. This guide covers compression fundamentals and practical recommendations for different file types.
Understanding Compression
Lossless Compression
Reduces size without losing any data. Original can be perfectly reconstructed:
- Best for: Documents, code, databases, archives
- Formats: ZIP, 7z, GZIP, PNG
- Typical ratio: 2:1 to 10:1 depending on content
Lossy Compression
Reduces size by discarding data, usually imperceptibly:
- Best for: Photos, videos, audio
- Formats: JPEG, MP4, MP3, WebP
- Typical ratio: 10:1 to 100:1
Archive Formats Compared
| Format | Compression | Speed | Compatibility |
|---|---|---|---|
| ZIP | Good | Fast | Universal |
| 7z | Excellent | Slow | Good |
| RAR | Very Good | Medium | Good |
| GZIP | Good | Fast | Universal |
| ZSTD | Excellent | Very Fast | Growing |
Recommendations
- Maximum compatibility: ZIP – everyone can open it
- Best compression: 7z – significantly smaller files
- Fastest: ZSTD – modern alternative gaining support
Compressing by File Type
Documents (PDF, DOCX)
- Already compressed – ZIP gains minimal space
- PDF optimization tools can reduce further (image recompression)
- Consider archiving multiple documents together
Images
Photos:
- JPEG is already lossy compressed
- Further compression loses quality
- Consider WebP for web delivery (30% smaller than JPEG)
- Keep originals, compress copies for sharing
Graphics/Screenshots:
- PNG is lossless – may compress well in ZIP
- Consider WebP or SVG for web graphics
Videos
Videos are typically already compressed (H.264, H.265):
- ZIP provides no meaningful reduction
- Re-encoding is only way to reduce
- H.265/HEVC is ~50% smaller than H.264 at same quality
- Consider resolution – 4K often unnecessary
See video sharing guide for video-specific guidance.
Code and Text
Highly compressible:
- Typical 10:1 compression ratio
- Any format works well (ZIP recommended for compatibility)
Best Free Compression Tools
7-Zip (Windows)
- Free, open-source
- Creates ZIP, 7z, GZIP, TAR
- Opens almost any archive format
- Excellent compression ratios
The Unarchiver / Keka (macOS)
- The Unarchiver: Free, opens everything
- Keka: Creates archives, more options
- Built-in Archive Utility for basic ZIP
PeaZip (Cross-platform)
- Free, open-source
- Supports 200+ formats
- Windows, Linux, portable
When NOT to Compress
Some files are already compressed or don't benefit:
- JPEG, PNG, GIF – Already compressed images
- MP4, MOV, MKV – Already compressed video
- MP3, AAC, FLAC – Already compressed audio
- ZIP, RAR, 7z – Already archives
- DOCX, XLSX – Already ZIP-compressed XML
Compressing these wastes time with minimal benefit.
Compression for Cloud Storage
GetShared and Compression
GetShared does NOT automatically compress your files – we preserve originals exactly. This means:
- ✓ Full quality maintained
- ✓ No unexpected changes
- ✓ Professional delivery possible
When to Compress Before Upload
- Archiving many small files (reduces overhead)
- Significantly compressible content
- Storage space is limited
When to Upload Uncompressed
- Recipients need individual files
- Files are already compressed formats
- Preview functionality needed
- Versioning needed for individual files
Compression and Security
Password-Protected Archives
ZIP and 7z support password protection:
- 7z with AES-256 is strong
- Standard ZIP encryption is weak (avoid)
- ZIP with AES (7-Zip creates these) is strong
However, GetShared's end-to-end encryption provides superior protection – consider sharing uncompressed with GetShared's security features instead.
Best Practices
- Match format to content – Text compresses well; video doesn't
- Use ZIP for sharing – Maximum compatibility
- Use 7z for archives – Better compression for storage
- Don't double-compress – ZIP of ZIP gains nothing
- Keep originals – Especially for lossy compression
- Test decompression – Verify archives before deleting originals
Conclusion
Compression is useful but not universal. Understand when it helps (text, documents, many files) and when it doesn't (photos, videos, already-compressed formats). For file sharing, GetShared's sending large files capability often eliminates the need for compression entirely.
sign up for GetShared and share files at full quality – 20GB free.
