PDF Compressor - Reduce PDF Size

📚 eBook preset values shown below. Customize any setting to override.

📐 Image Resolution

Target resolution for downsampling images. Higher DPI = better quality, larger files.

Color Images:

DPI

Grayscale Images:

DPI

Mono Images:

DPI

Screen: 72/72/300 · eBook: 150/150/300 · Printer: 300/300/1200 · Prepress: 300/300/1200

🖼️ JPEG Quality

Control the quality/size tradeoff for embedded JPEG images.

Quality:

40%

Screen/eBook: ~40% · Printer: ~60% · Prepress: ~90%. Lower = smaller files, more artifacts.

🎨 Color Conversion

Convert the entire PDF to grayscale for significant size reduction.

Convert to grayscale (removes all color)

Great for text-heavy documents where color isn't needed. Can reduce file size by 20-50%.

🔤 Font Options

Control how fonts are handled in the output PDF.

Subset fonts (only include used characters) Embed all fonts (ensures text displays correctly everywhere) Compress fonts

Subsetting reduces size significantly. Embedding ensures portability.

⚡ Optimization Features

Additional optimizations for better compression or web performance.

Detect duplicate images (finds and deduplicates repeated images) Optimize for fast web view (linearize PDF for progressive loading)

Duplicate detection helps with documents that repeat logos/headers. Fast web view is great for online PDFs.

📉 Downsample Method

Algorithm used when reducing image resolution.

Bicubic (best quality) Average (faster) Subsample (fastest)

Screen/eBook: Average · Printer/Prepress: Bicubic. Bicubic is smoother but slower.

📄 PDF Compatibility Level

Target PDF version. Newer versions may be smaller but less compatible with older readers.

Version:

All Ghostscript presets use PDF 1.5. Use 1.4 for maximum compatibility with older software.

🐕 About PDF Compressor

PDF Compressor uses Ghostscript WebAssembly to reduce PDF file sizes directly in your browser. Unlike simple image-based compression, this tool preserves vector graphics, text, and fonts while intelligently optimizing embedded images. Your files never leave your device.

✨ Quality Levels

Screen (72 DPI) – Maximum compression for on-screen viewing, email attachments

eBook (150 DPI) – Great balance of quality and size, perfect for digital documents

Printer (300 DPI) – High quality suitable for printing

Prepress (300+ DPI) – Maximum quality with color preservation for professional printing

🔒 Privacy First

All processing happens locally using WebAssembly. Your PDFs are never uploaded to any server. The Ghostscript engine runs entirely in your browser, ensuring complete privacy for sensitive documents.

💡 Tips

PDFs with lots of images benefit most from compression

Text-heavy PDFs may not shrink much since text is already efficient

The first compression may take a moment while the engine loads (~18MB)

Try different quality levels to find the best balance for your needs

PDF Compressor by Nobu Tools

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