Reduce the file size of any PDF document entirely in your browser. This tool re-renders each page via canvas at your chosen quality level using PDF.js and pdf-lib — no server uploads, total privacy.
Key Features of Compress PDF
- Three Optimization Profiles Choose from Screen (72 DPI), eBook (150 DPI), or Printer (300 DPI) to balance resolution and compression.
- Live Compression Metrics View exact kilobyte reductions and percentage shrink results in real-time before downloading.
- Vector Preservation Fonts, text, shapes, and vectors stay crisp and searchable; only raster images are downscaled.
- Zero Data Uploads Processing happens completely locally using browser canvas threads so your documents stay 100% private.
Compress PDF Examples
Shrinking Presentation Slides
Compress image-heavy presentation decks into lightweight versions for web uploads and emails.
Input
24.5 MB high-res master PDFOutput
3.2 MB optimized Screen PDF (~87% size reduction)How to Use Compress PDF
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1. Upload Your PDF
Drag and drop a PDF file onto the drop zone, or click to browse and select it from your computer.
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2. Choose a Compression Level
Select Screen (maximum compression, ~72 DPI), eBook (balanced, ~150 DPI), or Printer (high quality, ~300 DPI) from the Quality dropdown.
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3. Compress and Download
Click 'Compress PDF & Download' and the tool will re-render each page in your browser and prompt you to save the smaller file.
Common Use Cases for Compress PDF
- Job Resume Submissions Shrink scan-heavy resume portfolios to fit under strict online job board file size limits.
- Email Attachments Quickly compress bulky manuals or agreements to pass through standard 10MB email caps.
- School Assignments Optimize high-definition photo scans of homework or essays before uploading to university portals.
The Technical Details
The PDF Compressor handles downsizing locally by coordinating PDF.js and pdf-lib tasks. PDF.js initializes a headless viewport canvas context for each document page at a resolution calculated from your chosen DPI profile.
Once re-rendered, page canvas streams are converted to optimized JPEG blobs. The tool then compiles these images back into a sequential document using pdf-lib, embedding compressed frames into flat PDF sheets. This canvas translation pipeline keeps vectors intact while significantly reducing raster footprints.
Frequently Asked Questions
How much smaller will my PDF get?
Results vary by content. Image-heavy PDFs typically shrink 50–80% on Screen mode. Text-only PDFs see smaller reductions because text is already compact.
Does compression affect text quality?
No. Text, fonts, and vector graphics remain sharp at all compression levels. Only raster images are downscaled to the chosen DPI.
Is my PDF uploaded to a server?
No. The entire compression process runs in your browser using PDF.js and pdf-lib. Your file never leaves your device.
What is the maximum file size I can compress?
There is no hard limit imposed by the tool, but very large PDFs (hundreds of pages) may take longer to process depending on your device's memory and CPU.