What's the difference between Gzip and Deflate?

Gzip wraps the same Deflate-compressed data in a header and checksum, and is the more common format for standalone files (.gz). Raw Deflate is the identical compression algorithm without that extra header, and is often used inside other formats.

Does this work in every browser?

It needs a modern browser that supports the Compression Streams API (Chrome, Edge, Firefox, and Safari 16.4+). You'll see a clear message if your browser doesn't support it.

Gzip Compressor

Compresses any file into Gzip, Deflate, or raw Deflate format using the browser's own built-in compression API — no third-party library, and nothing is ever uploaded to a server. Compress several files at once and download the results individually or as a single ZIP, with a before-and-after size comparison for every file.

Productivity Tools Runs entirely in your browser

Your files are compressed entirely on your device using the browser's built-in compression API — nothing is uploaded to a server.

Drag any files here or choose them

You can select more than one file — any file type

Choose files

What this tool does

Compresses files as gzip, deflate or raw deflate, reporting the size saved, with batch processing.

When to use it

Preparing files for a web server that serves them compressed.
Testing a file's compressed size before publishing.
Compressing text or data files to reduce transfer size.
Producing a file in the compression format a particular system expects.

How to use it

Choose the format: gzip, deflate or raw deflate.
Put your files on the drop area or choose them.
Download each compressed file individually, or take them all with "Download all as ZIP".

A practical example

Input

A large text file as gzip.

Output

The compressed file with the percentage size saving reported.

Limitations

Already-compressed files — images, video, archives — save essentially nothing, and the tool reports no meaningful savings rather than handing you a larger file.
The three formats are close but not interchangeable; pick the one the consuming system expects.
This compresses one file at a time rather than a folder; to bundle files, use the ZIP Archive Creator.