Is there a file size limit for zipping in the browser?

Practical limits come from your device memory, not the tool: everything is processed in RAM in your browser. Very large archives may be slow or hit memory limits on low-RAM devices — the tool warns you about large inputs before you start.

Are the files in my ZIP uploaded?

No. The archive is parsed and rebuilt entirely inside your browser tab. Extracted file names and contents stay on your device and are never transmitted or logged.

Can I open a password-protected ZIP?

Encrypted ZIP archives are not supported in this release. The tool detects them and tells you plainly rather than failing silently.

Why did re-compressing my ZIP not make it smaller?

ZIP stores already-compressed data. If the archive was created with strong settings, or mostly contains media that is compressed by design, there is nothing left to squeeze. The tool shows the true measured size so you can decide whether to keep it.

Create and extract ZIP archives — privately

Bundle files into a ZIP archive, open an existing ZIP to get its contents back, or repack an archive with stronger compression. Everything happens in your browser; your files never touch a server.

Open the ZIP compressor tool Runs entirely in your browser — files never leave your device.

What this tool does

Creating a ZIP is the everyday way to send several files as one: select your files, and the tool packs them locally with real DEFLATE compression. Extracting works the same way in reverse — the archive is parsed in your browser and each entry is offered as a separate download, with no upload in either direction.

Re-compressing an existing ZIP can help when it was created with weak settings, but archives are already compressed data, so honest gains may be small or zero. The tool measures the real result and reports it, even when the output ends up larger.

How to make a ZIP file without installing anything

Choose your files. Select multiple files in the home-page drop zone, or drop an existing ZIP to unpack it.
Pack or unpack. Create a new ZIP from the selection, extract an archive, or repack it with stronger compression.
Download. The ZIP (or the extracted entries) is produced locally and saved by your browser.

Supported operations

This list is generated from CompressKit's capability registry — only implemented and tested operations appear here.

Create archive

Build a new ZIP archive from the files you select, with real DEFLATE compression.
Extract content

Open a ZIP and download its entries individually. No file inside ever leaves your browser.
Reduce file size

Repack an existing ZIP with stronger compression. Gains depend on the original settings and content types.

Frequently asked questions

Is there a file size limit for zipping in the browser?: Practical limits come from your device memory, not the tool: everything is processed in RAM in your browser. Very large archives may be slow or hit memory limits on low-RAM devices — the tool warns you about large inputs before you start.
Are the files in my ZIP uploaded?: No. The archive is parsed and rebuilt entirely inside your browser tab. Extracted file names and contents stay on your device and are never transmitted or logged.
Can I open a password-protected ZIP?: Encrypted ZIP archives are not supported in this release. The tool detects them and tells you plainly rather than failing silently.
Why did re-compressing my ZIP not make it smaller?: ZIP stores already-compressed data. If the archive was created with strong settings, or mostly contains media that is compressed by design, there is nothing left to squeeze. The tool shows the true measured size so you can decide whether to keep it.

Ready to try it?

The ZIP compressor tool runs on this site with no upload step — your file is processed by your own browser and saved back to your device.

Open the ZIP compressor tool