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Free browser tools that respect your files — everything runs locally, nothing is uploaded.

Compress FilesDecompress Files

File Compressor

Compress your files with various compression formats. All processing happens directly in your browser - no data is sent to any server.

Select Output Format

Upload a file to start converting

By Joseph OrdunaHow this works

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. [1]
    MDN — WebAssembly (Wasm)
    Documentationdeveloper.mozilla.orgAccessed Apr 21, 2026
  2. [2]
    FBI Denver — Free Online File Converter Scam Warning
    Official sourcefbi.govAccessed Apr 21, 2026

    Public service announcement on malicious online file converters.

  3. [3]
    PKWARE — APPNOTE (ZIP file format specification)
    Official sourcepkware.cachefly.netAccessed Apr 21, 2026
Joseph Orduna
Founder & Software Engineer

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).

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