GZIP Compress / Decompress
Free online GZIP compression and decompression powered by pako in your browser. Base64 or Hex output, with original/compressed size and ratio. Computed locally, nothing uploaded.
Runs locally · data never uploaded
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How to use
What it does
GZIP is a widely used lossless compression format (the Linux gzip command and HTTP Content-Encoding: gzip both use it). This tool runs on the pako library inside your browser, so all compression and decompression happen locally.
- Compress: UTF-8 encodes the text and compresses it; the output can be Base64 or Hex for easy copying and transport.
- Decompress: accepts GZIP data as Base64 or Hex and restores the UTF-8 text.
- After compression it shows the original size, compressed size and ratio so you can see the savings at a glance.
Example
Compress "Hello, GZIP!" with Base64 output and you get a base64 string starting with H4sI (the typical GZIP stream prefix). Paste that string back into "Decompress" mode to recover the original text.
Common uses
- Passing compressed text between frontend and backend in a compact form
- Verifying that GZIP data returned by a server decompresses correctly
- Quickly estimating the compression gain of a piece of text
FAQ
Q1.Should I pick Base64 or Hex?
Both just encode the binary GZIP data as text. Base64 is more compact (~4 chars for 3 bytes) and suited for APIs; Hex is more readable for debugging. When decompressing, use the same encoding chosen during compression.
Q2.Why did compression make it bigger?
GZIP has a fixed header overhead, so very short input can show "negative" compression. You usually need a few hundred bytes before meaningful savings appear.
Q3.It says "not a valid GZIP stream" — what now?
The input is corrupted, truncated, or the encoding is wrong (Base64/Hex mismatch). Make sure you copied it fully and pick the same output encoding used during compression.
Q4.Is my data uploaded?
No. Compression and decompression run entirely in your browser; the content is never sent to any server.
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