File Compressor
Compress your files with various compression formats. All processing happens directly in your browser - no data is sent to any server.
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Files are processed locally and never uploaded
Up to 500 MB · up to 50 files
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Upload a file to start converting
Quick Answer
File compression reduces file size by removing redundancy using algorithms like ZIP, GZIP, or 7z. To compress files, select files or folders, choose a compression format, and create the archive. Compressed files are smaller for storage and faster to transfer. ZIP is the most universally compatible format.
Key Features
- ZIP is the most widely compatible compression format across all platforms
- 7z offers better compression ratios but requires compatible software
- GZIP is commonly used for web content and Linux systems
- Compression works best on text, documents, and uncompressed data
- Already compressed files (JPG, MP3, MP4) won't compress much further
- Password protection can be added to compressed archives
- Browser-based compression processes files locally without uploads
How this conversion works
Files are compressed into a ZIP archive using DEFLATE per the PKZIP APPNOTE specification. Already-compressed formats (JPG, MP4, MP3, etc.) compress very little — this is expected.
What this tool can’t do
- Extremely large files are bounded by your device memory, not by server capacity. A very low-memory tablet may fail to load a 4K video where a desktop completes in seconds.
- WebAssembly codec support lags slightly behind native desktop tools. For obscure or experimental codecs, a native tool (like desktop FFmpeg) is still the right choice.
When to consult a professional
If you need batch-processing millions of files, a server-side pipeline will outperform per-user browser conversion. For DRM-protected media, a legitimate licensed reader is required.
Sources
- [1]MDN — WebAssembly (Wasm)Documentationdeveloper.mozilla.orgAccessed Apr 21, 2026
- [2]FBI Denver — Free Online File Converter Scam WarningOfficial sourcefbi.govAccessed Apr 21, 2026
Public service announcement on malicious online file converters.
- [3]PKWARE — APPNOTE (ZIP file format specification)Official sourcepkware.cachefly.netAccessed Apr 21, 2026
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).