7-Zip Online — Compress and Extract 7z Files Free
Create and extract 7z archives using real 7-Zip compiled to WebAssembly — no installation required. Runs entirely in your browser for maximum privacy.
Drop files here or click to browse
Select files to compress into a 7z archive
How 7-Zip Online Works
- 1Select Compress or Extract using the tab at the top.
- 2Drop your files (or .7z archive) onto the dropzone. The 7-Zip WASM engine loads on first use.
- 3Click Create 7z Archive or Extract Files to process your archive.
- 4Download the resulting
archive.7zor individual extracted files.
Why 7z Offers the Best Compression
7-Zip uses the LZMA2 algorithm, which builds a large dictionary of repeated patterns across all files in the archive simultaneously. This "solid archive" approach means highly similar files (like source code files in the same project) compress together far better than they would individually in a ZIP.
Tips for 7z Archives
Best for source code
Repositories full of similar .js, .ts, or .py files see exceptional compression with 7z. LZMA2 can often achieve 60–80% reduction.
WASM loads once
The 1.6 MB engine loads once per browser session. After that, compressing and extracting multiple files is instant.
Compatibility
7z is supported natively by 7-Zip on Windows, and via p7zip or Keka on macOS/Linux. It is not natively supported by Windows Explorer without the 7-Zip app.
When to use ZIP instead
If the recipient may not have 7-Zip installed, use the ZIP tool for maximum compatibility. Both tools are free and run in the same browser.
Frequently Asked Questions
Is this the real 7-Zip?
Yes. It uses 7z-wasm, which is the official 7-Zip source code compiled to WebAssembly via Emscripten. You get the same compression algorithm as the desktop application.
Why does the first run take a moment to start?
The 7-Zip WebAssembly binary (~1.6 MB) loads on first use. After it is cached by your browser, subsequent uses start instantly.
Are my files uploaded to any server?
No. Everything runs locally in your browser tab. The WASM binary is served as a static file, and your data never leaves your device.
What formats can be extracted?
The extract mode currently handles .7z archives. For ZIP and TAR extraction, use the dedicated Unzip Online and Untar Online tools.
How does 7z compression compare to ZIP?
7z typically achieves 30–70% better compression than ZIP on text files and executables, at the cost of slower compression and extraction speed.
Is there a file size limit?
No server-side limit. The constraint is your browser's available memory. Large archives (several hundred MB) work fine on desktop browsers.