How to use
- Drag and drop your file into the dropzone, or click to select one from your device.
- The mode is auto-set to Decompress for .gz and .tgz files, or Compress otherwise — change it if needed.
- Click Run to gzip the file into a .gz, or gunzip a .gz back to its original bytes.
- Check the before and after sizes, then download the resulting file to your device.
Frequently asked questions
Are my files uploaded to a server?
No. All gzip compression and decompression runs 100% in your browser. Your file never leaves your device and nothing is uploaded, so your data stays completely private.
What file types can I compress or decompress?
You can gzip any single file of any type into a .gz. For decompression, drop a .gz or .tgz file and the tool gunzips it back to the original bytes.
Does gzip compression reduce quality?
No. Gzip is lossless, so decompressing a .gz always returns the exact original bytes with no quality loss. It works best on text, logs, CSV, and other non-compressed data.
Is there a file size limit?
There is no fixed limit, but because everything is processed in your browser's memory, very large files depend on your device's available RAM.
What happens to the file name when I decompress?
A .gz extension is stripped from the name (for example data.csv.gz becomes data.csv), a .tgz becomes .tar, and any other input gets an .out suffix so the original is never overwritten.
Can I compress multiple files or a folder at once?
No. This tool works on one file at a time and does not bundle multiple files or folders into a single archive. Combine files into an archive first, then gzip that.
About this tool
Free gzip tool: compress any file to a compact .gz or decompress a .gz back to the original. Runs 100% in your browser with no uploads, keeping files private.