Optimize
Reduce ZIP File Size
Upload a ZIP and this tool attempts to reduce its size: removes system junk (.DS_Store, __MACOSX, Thumbs.db), recompresses files that were not optimally compressed, and shows a breakdown of where the size is coming from. Shows before and after comparison.
Input formats
Output formats
Common uses
- Reduce a ZIP for email attachment
- Prepare a ZIP for a form with size limits
- Optimize a project archive for distribution
- Find out which files are making a ZIP large
Limitations
- Already-compressed files (JPG, PNG, MP4, MP3, PDF, existing ZIPs) will not shrink significantly.
- Maximum compression savings depend on the types of files in the archive.
- For significant size reduction of images, use dedicated image compression tools first.
Frequently asked questions
ZIP compression is most effective on text, code, and uncompressed files. If your archive contains mainly images, videos, PDFs, or other already-compressed files, the ZIP cannot compress them further — the data is already compressed internally.
Compress the images themselves first using an image compression tool, then recreate the ZIP. Recompressing already-compressed images inside a ZIP will not help significantly.
Not automatically, but the tool shows duplicate files and you can use the Remove Files from ZIP or Duplicate Finder tools to clean them.