Gzip a file
Drop a file and download its .gz. Gzip is lossless single-file compression: it shines on text, CSV, JSON, and logs. Everything runs in your browser; the file is never uploaded.
What gzip does
Gzip compresses a single file losslessly: it finds repetition in the bytes and packs them tighter, then writes a .gz file. Decompressing it later — with gunzip, the gzip command, or most archive utilities — restores the original file byte-for-byte. Nothing is lost. This tool runs the compression in your browser, so the file never leaves your device.
Because gzip looks for redundancy, it works best on text-like data: CSV, JSON, logs, HTML, SVG, and source code often shrink dramatically. A large log or data export is the ideal candidate.
When gzip won't shrink a file
Files that are already compressed have almost no redundancy left for gzip to remove. JPG, PNG, GIF, MP4, MP3, ZIP, and most PDFs fall into this group: gzipping them shrinks them little or not at all, and the few bytes of gzip header and footer can make the .gz slightly largerthan the original. That is expected, not a fault — the before/after size is shown exactly as it came out, and nothing is claimed that wasn't achieved.
Gzip also holds exactly one file — it is a compressor, not an archive format. If you need to bundle several files into a single download, reach for a ZIP instead, which packs many files into one archive.
Is it private?
Yes. The compression is a browser API running on your own machine. Nothing is uploaded, stored, or seen by us. There is no server to send files to.
Frequently asked questions
- What kind of file should I gzip?
- Gzip works best on text-like files: CSV, JSON, logs, HTML, SVG, source code, and other documents with repetitive content. Those typically shrink a lot. Files that are already compressed — JPG, PNG, GIF, MP4, MP3, ZIP, and most PDFs — have little redundancy left, so gzip barely shrinks them and may even add a few bytes.
- Can I gzip several files into one .gz?
- No. Gzip compresses exactly one file; it is not an archive format. To bundle several files together, use a ZIP instead, which holds many files in a single archive.
- Is gzip lossless? Will I get my exact file back?
- Yes. Gzip is lossless: decompressing the .gz with gunzip (or any tool that reads gzip, including the gzip command and most archive utilities) gives back the original file byte-for-byte.
- Are my files uploaded to a server?
- No. The compression runs on your device in the browser. Your file is never sent anywhere, and there is no server to send files to.
- Is it free, and do I need an account?
- It is free with no sign-up. Drop a file and download its .gz. The before/after size is shown exactly as it came out.