Compress PDF
Reduce PDF file size
This free online compress pdf runs in your browser and is part of our PDF Tools collection.
Compress PDF
Reduce PDF file size while maintaining quality
Compression Tips
- Light: Minimal compression, maintains high quality (5-15% reduction)
- Medium: Balanced compression (15-40% reduction)
- Heavy: Maximum compression, may reduce quality (40-70% reduction)
- Image compression has the biggest impact on file size
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Instant In-Browser Execution
Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security
Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive
Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever
No subscription fees, no signups, and no software installations.
How to Use the Online Compress PDF
1
Upload Heavy PDF
Select a large PDF file to inspect its original size in megabytes.
2
Select Compression Level
Adjust the compression slider between Light (maximum visual fidelity), Medium (balanced), and Heavy (maximum size reduction).
3
Toggle Optimization Flags
Choose whether to compress embedded bitmap images, strip redundant metadata, and optimize PDF structural streams.
4
Compress & Download
Click "Compress PDF" to run stream optimization and download the compact PDF with an immediate size savings report.
Frequently Asked Questions
Common questions about using this free online compress pdf.
How does in-browser PDF compression work? ▾
Compression works by downsampling high-DPI embedded raster images, stripping unnecessary document metadata (such as editing histories and thumbnail streams), and deflating uncompressed object streams.
Will compressing my PDF make the text blurry? ▾
No. True vector fonts and text glyphs in PDFs are stored as geometric curves and remain 100% sharp regardless of compression level. Only embedded photographs or raster scans are compressed.
Why did my PDF only shrink by a small percentage? ▾
If a PDF consists primarily of raw vector graphics, already-optimized WebP/JPEG images, or pre-compressed scans, further compression potential is naturally limited without degrading visual clarity.
Can I compress password-locked PDFs? ▾
To compress a PDF, the file must be decrypted so the browser can parse its internal stream dictionary. Unlock the file first before compressing.
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