PDF Compressor

Overview

This PDF compression tool reduces file size by lowering image resolution and optimizing file structure. By default it runs entirely in your browser — no upload required. Switching to cloud mode uploads the file to a server and typically achieves higher compression ratios. The single-file limit is 100 MB, and results show original size, compressed size, and percentage saved.

How much compression to expect

Results depend heavily on what the PDF contains:

  • Text-only PDFs (exported presentations, office documents): local compression saves 10–30%; cloud is similar
  • Scanned PDFs (color A4 scan at 300 DPI): local saves ~20–50%; cloud on "Screen" resolution can save 60–80%
  • Image-heavy PDFs (product catalogs, lookbooks): cloud + image quality set to 60 can save 50–70%

If compression would make the file larger, the tool keeps the original and notes "compressed file was not smaller, original retained."

Local vs. cloud: when to switch

Stay in local mode when

  • File contains sensitive information
  • The PDF is mostly text — local and cloud results will be similar
  • Lossless preset is enough to meet your size requirement

Switch to cloud mode when

  • Source is a scanned document with many images
  • Local balanced preset still leaves the file too large
  • You need the "Screen" (72 DPI) resolution for online sharing

Cloud mode: image quality and resolution tradeoffs

The resolution preset controls how aggressively images are downsampled:

  • Screen (72 DPI): smallest output, suitable for emailing or web sharing — not for printing
  • Ebook (150 DPI): readable on screen and mobile, moderate size
  • Printer (300 DPI): retains enough quality to print
  • Prepress: high resolution, for professional print workflows

Image quality (1–100) works alongside the resolution preset. Start at 80 — if the file is still too large, drop to 60. Below 40, text in scans becomes visibly blurry.

Handling password-protected PDFs

If the source PDF has a password, enter it in the "PDF Password (optional)" field. Both local and cloud modes support this. The password is used only to unlock the file for processing and is not stored.