GZIP compress a file

What gzip is and how it differs from ZIP

Gzip compresses a single file. It does not bundle multiple files together, which is why on Unix systems you see the two-step form .tar.gz: tar collects the files, gzip compresses the result. On its own, gzip is the compression method behind most of the web: servers send HTML, CSS and JavaScript gzip-compressed, and browsers decompress it on arrival. It uses the same DEFLATE algorithm as ZIP, so the compression ratios are similar, but the container is simpler and the file just gets a .gz suffix.

What this tool produces

Each file you drop in becomes its own .gz file using the compression engine built into your browser. The result is a standard gzip file that gunzip, 7-Zip, WinRAR, macOS Archive Utility and every web server understand. The original file name is kept with .gz appended.

When gzip is the right choice

• Pre-compressing web assets. Some static hosts and CDNs serve a .js.gz or .css.gz file directly if it exists next to the original, saving the server from compressing on every request.
• Shrinking log files before archiving or attaching them to a support ticket. Logs compress by 90% or more.
• Database dumps and CSV exports that need to be emailed or uploaded. A 200 MB SQL dump is commonly 20 MB gzipped.
• Matching a system that expects .gz, such as a data import that reads gzipped CSV, or a deployment pipeline.
• Single large files where a ZIP container adds nothing.

Where it does not help

Gzip cannot shrink data that is already compressed. JPG, PNG, MP4, MP3, PDF and modern Office files will come out roughly the same size or fractionally larger. For photos and video, use the dedicated image and video compressors instead.

Restoring the file

To get the original back, use the gunzip tool, or on the command line gunzip filename.gz. Because gzip is a single-file format, there is no listing step; decompressing simply yields the original file. Compression runs on your device using the browser's native engine, so nothing is uploaded and large files are handled quickly.