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Compression Toolkit

Compress real files in-browser with dedicated PDF, Docs, and Image subtools.

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  • Works offline once loaded
  1. 1Pick file
  2. 2Intensity
  3. 3Download
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What this does

Estimate how much smaller a folder will get if you compress it — before you commit.

Drop a folder or set of files, get a per-file estimate of savings based on content type. Text and code compress dramatically (70-90% smaller). Photos, videos, and PDFs barely shrink (2-5%). The estimator tells you what's actually worth compressing — and what to leave alone.

How estimation works

  1. 1

    Drop a folder or files

    Any combination of file types. The tool reads file sizes and extensions — no actual contents leave your browser.

  2. 2

    Per-file estimate appears

    Each file is categorized by type. Text/code shows high savings predictions (70-90%). Photos/video/audio show near-zero. Office docs show middling (10-40%).

  3. 3

    Decide what's worth compressing

    If your total folder is 5 GB and the estimator predicts only 4% overall savings, compression isn't worth the time. If it predicts 60%, you save 3 GB.

When to estimate first

Deciding whether to compress an archive

100 GB old project folder. If estimator says 5% savings, skip compression (waste of CPU). If 50%, compress before backup.

Server log compression decisions

Logs typically compress 90%+. The estimator confirms before you set up a compression schedule.

ZIP-vs-send-multiple decision

Sending 10 files individually vs. ZIPing first. If files barely compress, ZIPing only adds organizational benefit, not size savings.

Cloud storage cost-benefit

Cold storage often charges for retrievals. Heavy compression saves storage cost but slows retrieval. Estimator helps decide threshold.

What compresses well

Same rules as ZIP — DEFLATE is great on text, useless on already-compressed media.

  • Text, code, JSON, XML, CSV

    Best for: 70-90% reduction. Always worth compressing.

  • Log files

    Best for: Up to 95% reduction — repetitive patterns ideal for DEFLATE.

  • Old Office (.doc, .xls)

    Best for: 30-40% reduction.

  • Modern Office (.docx, .xlsx)

    Best for: 10-20% — internal ZIP already compresses these.

  • Photos / video / audio

    Best for: Near-zero reduction. Skip ZIP for organization only.

    Watch out: If you really need savings, use format-specific compressors (image, video tools).

  • PDFs

    Best for: 5-10% on top of PDF's internal compression.

    Watch out: Use a PDF compressor instead for meaningful savings.

Compression-estimate tips

  1. 01

    Estimates assume DEFLATE (ZIP)

    Other algorithms (7z LZMA, zstd, brotli) can do better, especially on already-near-optimal data. Estimator's predictions are conservative.

  2. 02

    Bigger files compress slightly better

    DEFLATE works on a sliding window. Bigger files have more repetition patterns to exploit, so a 1 GB log file may compress better than 100 individual 10 MB logs.

  3. 03

    Don't compress small files individually

    ZIP has per-file overhead (~50 bytes). For files under 500 bytes, the overhead can exceed the savings. Bundle them first.

  4. 04

    Encryption changes compression dramatically

    Already-encrypted files (password-protected ZIPs, encrypted backups) don't compress at all — encrypted data looks random to DEFLATE.

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Frequently asked

Yes. This tool runs in-browser and generates a downloadable compressed output for PDF, supported document, and image files.

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