Compress a ZIP to 1MB
You can't shrink a ZIP by re-zipping it — it's already compressed. This tool opens your archive, recompresses the images and PDFs inside to fit a size you choose, and repacks it. Pick a target, drop your ZIP, and download a smaller one. Everything happens in your browser.
How shrinking a ZIP actually works
A ZIP file stores its contents already compressed with DEFLATE, so running it through another zipper barely helps. The real savings come from the contents: photos and PDFs are usually the heavy items, and they can be recompressed to a fraction of their size.
This tool distributes your chosen size budget across the images and PDFs in the archive, then recompresses each toward its share using a binary search on quality. Files that are already compressed — video, audio, other archives — are left untouched, and the tool tells you when they make a small target impossible.
What can be shrunk inside a ZIP
| Inside the ZIP | Can it shrink? | How |
|---|---|---|
| Photos (JPG, PNG, WebP, HEIC) | Yes — a lot | Recompress at lower quality / smaller dimensions |
| PDFs | Yes — often | Strip metadata, recompress embedded images |
| Text, code, CSV, JSON | A little | Already small; limited gains |
| Video & audio (MP4, MP3) | Usually not | Already compressed codecs |
Frequently asked questions
Can you really compress a ZIP to 1MB?
A ZIP is already compressed, so re-zipping it saves almost nothing. We get a ZIP smaller by recompressing the images and PDFs inside it (lossily) until the total fits your target. If the archive is mostly already-compressed content like video or audio, hitting a small target may not be possible — the tool tells you honestly and suggests removing files or splitting the archive.
Is the compression lossless?
No. Images and PDFs are recompressed lossily to save space, so there is some quality loss — usually minor for photos. Files we cannot safely shrink (text, video, audio, other archives) are passed through untouched.
What about videos or audio inside the ZIP?
In this version, only images and PDFs are recompressed; video and audio are kept as-is. If those make up most of your archive, the achievable size is limited.
Are my files uploaded to a server?
No. The ZIP is opened, recompressed, and repacked entirely in your browser. Nothing is uploaded.