PDF Compressor

Compress PDF files with advanced quality and resolution settings

About PDF Compressor

Overview

PDF Compressor is a browser-based tool that reduces PDF file size using advanced compression techniques. Upload a PDF and choose from various compression settings including image quality, resolution, metadata removal, and grayscale conversion. The tool optimizes images within the PDF while preserving text quality, making your files smaller for easier sharing and storage. All processing happens locally in your browser for complete privacy.

Features

  • Adjustable image quality from 30% to 100%
  • Four DPI options: 72, 150, 200, 300 DPI
  • 150 DPI default (balanced quality and file size)
  • Remove document metadata and properties
  • Convert to grayscale option for maximum compression
  • Real-time compression preview with size calculation
  • Preserves text quality while optimizing images
  • 100% browser-based processing - no server uploads
  • Dark mode support for comfortable viewing

How to Use

  1. Click "Choose PDF File" or drag and drop a PDF file into the upload area
  2. Adjust image quality slider from 30% to 100% (default: 70%)
  3. Select DPI: 72 (smallest), 150 (balanced/recommended), 200 (good), or 300 (best)
  4. Optionally enable metadata removal to reduce file size further
  5. Optionally convert to grayscale for maximum compression
  6. Wait for the compression preview to calculate (automatic)
  7. Click "Download Compressed PDF" to save your optimized file

FAQ

Is my data safe when using PDF Compressor?

Yes, absolutely. All PDF processing happens entirely in your browser using JavaScript. Your files are never uploaded to any server or transmitted over the internet. The compressed PDF is created locally on your device and downloaded directly to your computer.

How much will my PDF be compressed?

Compression depends on your PDF content and settings. PDFs with many images can be reduced by 50-90%, while text-heavy PDFs may only see 10-30% reduction. Lower quality percentage and resolution (DPI) provide more compression. Using 30% quality + 72 DPI + Grayscale gives maximum compression.

Will the text quality be affected?

No, text quality is always preserved. The compression only affects embedded images. Text, fonts, and vector graphics maintain their original quality regardless of your compression settings.

What are the recommended settings?

For screen viewing/sharing: 70% quality + 150 DPI (default). For maximum compression: 30-40% quality + 72 DPI + grayscale. For maintaining quality: 80-100% quality + 200-300 DPI. Enable metadata removal in all cases for extra compression. Start with defaults and adjust based on the preview file size.

What's the difference between Quality and DPI?

Quality (30-100%) controls JPEG compression - how much image detail is preserved during compression. Higher quality = more detail = larger files. DPI (Dots Per Inch) controls render resolution - how many pixels to use when rendering the PDF to images. PDFs use 72 points per inch as base, so 150 DPI = 2.08× scale = 2.08 pixels per point. Higher DPI = more pixels = better clarity = larger files. Both settings work together to balance quality and file size.

Can I compress an already compressed PDF?

Yes, but results vary. If a PDF is already well-compressed, you may see minimal additional reduction. It's best to use this tool on original, uncompressed PDFs for maximum effectiveness.