What This Tool Does
This tool rebuilds a ZIP archive with the strongest available compression to reduce its size. It unpacks every entry and repacks it with maximum DEFLATE, which often removes bytes that an average ZIP stored wastefully.
You receive a size report showing the original size, the new size, and the percentage saved. If the archive cannot be made smaller, the tool reports that truthfully rather than claiming a reduction.
How It Works
The ZIP entries are read and re-encoded at the maximum compression level into a fresh archive. The output file is then compared with the input file to calculate the real size difference, and the report is generated from those measured numbers.
Step by Step
- 1
Upload the ZIP file.
- 2
Click Reduce Size.
- 3
Wait for the recompression to finish.
- 4
Read the size report and download the optimized ZIP.
What Reduces Well
- Stored (uncompressed) ZIP entries shrink substantially.
- Word documents, spreadsheets and text files compress well at maximum level.
- Video, photos and music rarely shrink further; the report reflects that.
Troubleshooting
- Only valid ZIP archives are accepted.
- Media-heavy archives may already be at their minimal size.
- For a floor on shared attachment sizes, pair this with Split ZIP File.