Repack a ZIP using maximum DEFLATE compression and optional metadata cleanup.
Best results usually come from text, CSV, XML, code and uncompressed documents.
JPEG, WebP, MP4, MP3 and many PDFs already contain compressed data. Repacking them may save little or can make a slightly larger archive.
The ZIP remains on your device during processing.
Settings, real-world decisions, release checks and limitations.
The ZIP compressor reads an existing archive and repacks its entries with maximum DEFLATE compression. It can also remove common system files such as .DS_Store, Thumbs.db and __MACOSX metadata.
Not every ZIP can become smaller. JPG, PNG, WebP, MP4, MP3, PDF and other compressed formats may have little remaining redundancy, while text, CSV, JSON, XML and source code usually compress more effectively.
| Setting or choice | Choose it when | Trade-off |
|---|---|---|
| Maximum DEFLATE | Text, CSV, JSON, XML, logs and source code | More CPU time |
| Remove system files | Shared archives containing __MACOSX or .DS_Store | Do not remove files whose purpose you do not understand |
| Keep original if smaller | Recommended for mixed media archives | The output may simply remain the original |
| Compress sources first | Best when photos or PDFs dominate | Changes the files, not only the container |
Inspect which file types occupy most of the archive.
Remove unnecessary duplicates and optional system metadata.
Repack with maximum compression and compare against the original.
Open the result and verify important entries before deleting anything.
Keep the original; this is common with already-compressed media.
Repack smaller archives or reduce source files first.
Disable metadata removal and run again.
They already use specialized compression that removes much repetition.
It repacks their bytes; optional system files can be omitted.
It can package it, but size reduction is usually negligible.
Deleting unnecessary files or reducing large images/PDFs often matters more than ZIP level.
It is strongest for DEFLATE but may take longer and still produce the same size for some data.