Compress PDF – Free Online Tool
Free online PDF compressor with image recompression, metadata removal, and adjustable quality slider. 100% client-side — your files never leave your device.
The Most Powerful Free PDF Compressor Online
Our PDF compressor goes far beyond basic structural optimization. It uses advanced image recompression via the Canvas API, metadata stripping, form flattening, and unused object removal — all running 100% in your browser. Adjust image quality from 10% to 100% with a precision slider, set a target file size, and see exactly how much space each technique saves. No file uploads, no server processing, no privacy risks.
Advanced Compression Engine — Client-Side
We use pdf-lib to parse PDF structure, extract embedded images, recompress them through the HTML5 Canvas API at your chosen quality level, and rebuild the PDF with optimized streams. This approach handles the biggest source of PDF bloat — embedded images — which typically account for 40-80% of file size. Combined with metadata removal and object stream compression, you get results rivaling server-side tools like Ghostscript.
Why Choose Our PDF Compressor Over Competitors
Unlike iLovePDF, Smallpdf, or Adobe Acrobat Online, we never upload your files to any server. Your tax returns, contracts, medical records, and personal documents stay on your device. Plus, we offer features no competitor has: a granular quality slider (not just 2-3 presets), per-page size analysis showing which pages are heaviest, a detailed compression breakdown, and the ability to set an exact target file size.
Who Benefits from This PDF Compressor
Students compressing assignments for email submission, professionals sharing contracts and reports, healthcare workers handling HIPAA-sensitive documents, legal teams managing discovery files, real estate agents optimizing property listings, and anyone who needs to fit a PDF under an email attachment limit. Our tool handles documents up to 100MB with real-time progress tracking.
How to Use Compress PDF
- 1
Upload your PDF by dragging it onto the upload zone or clicking to browse
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Adjust compression settings — use the quality slider to balance file size vs image quality, toggle metadata removal and form flattening, or set a target file size
- 3
Click Compress and download your optimized PDF. The detailed breakdown shows exactly what was compressed and by how much
Frequently Asked Questions
Everything you need to know about the Compress PDF.
Is this PDF compressor really free and unlimited?
Yes, completely free with no daily limits, no file size restrictions, and no watermarks. Because everything runs in your browser using your device's processing power, there are no server costs for us to recoup. Compress as many PDFs as you want.
How much can I reduce my PDF file size?
Results vary based on content. Image-heavy PDFs (scanned documents, presentations with photos) typically see 40-80% reduction. Text-heavy PDFs with few images usually achieve 10-30% reduction through metadata removal and structural optimization. The compression breakdown shows exactly where space was saved.
Does compression reduce the quality of my PDF?
You have full control. The image quality slider lets you choose from 10% (maximum compression, noticeable quality loss) to 100% (lossless image preservation). At 70-80%, most documents look identical to the original while being significantly smaller. Text, fonts, and vector graphics are never affected.
Is my PDF data safe and private?
Absolutely. Your PDF never leaves your device — all processing happens locally in your web browser using JavaScript and the Canvas API. We have no servers that receive, store, or process your files. This makes our tool ideal for sensitive documents like tax returns, medical records, legal contracts, and financial statements.
Can I compress a PDF to a specific file size?
Yes! Use our target file size feature to specify your desired output size (e.g., 'under 5MB for email'). The tool automatically calculates and applies the optimal image quality setting to achieve your target while maintaining the best possible visual quality.
Why is my compressed PDF larger than the original?
This can happen with PDFs that are already heavily optimized or use advanced compression algorithms. In this case, we automatically detect the issue and keep your original file. Try lowering the image quality slider or enabling additional compression options like metadata removal.