LZW Compressor
Compression · Free Online Tool
LZW dictionary compress/decompress (classic GIF algorithm).
Click "Compress" to run...Pure JS
No native APIs — works on any browser, including Safari without CompressionStream.
12-Bit Codes
Uses the classic 9→12 bit variable-width code scheme with CLEAR/EOF markers.
Base64 Transport
Output is base64-encoded for safe copy/paste between systems.
How to Use LZW Compressor
- 1Enter or paste the text you want to compress.
- 2Select the compression algorithm (gzip, deflate, or brotli).
- 3Click compress to reduce the data size.
- 4Copy or download the compressed output.
Features
- ✓100% free — no signup, no subscription, no ads
- ✓Runs entirely in your browser — data never leaves your device
- ✓Fast and lightweight — instant results
- ✓Cross-platform — works on desktop, tablet, and mobile
Frequently Asked Questions
What compression algorithms are supported?
We support gzip, deflate, and brotli compression algorithms for text data.
Is there a file size limit?
Since tools run in your browser, the limit depends on your device memory. Most tools handle several megabytes without issues.
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Raw Deflate Compressor
Raw Deflate stream without zlib header compress/decompress.
LZ-String Compressor
lz-string compress/decompress for short text in URLs/LocalStorage.
LZUTF-8 Compressor
LZUTF-8 compress/decompress optimized for UTF-8 text.
Learn the concept
Learn the concept
Understand the programming ideas behind this tool.