PDF Compressor
Upload a PDF and compress it using quality settings. See the estimated size reduction before downloading the compressed file.
PDF Compressor
Select a PDF to compress
Click or drag PDF here
Compressed PDF reduces file size by adjusting image quality and removing unnecessary objects. Quality level determines the balance between size reduction and visual fidelity.
How PDF Compression Works
PDF compression reduces file size by:
**Image downsampling**: Reducing the resolution of embedded images - Low quality: 72 DPI, significant size reduction - Medium quality: 150 DPI, balanced - High quality: 300 DPI, minimal quality loss
**Font embedding optimization**: Subsetting fonts, removing unused glyphs **Metadata removal**: Stripping author, creator, and other metadata **Object compression**: Compressing stream objects and compression filters
**Quality trade-off**: - Low: Maximum size reduction (often 60-80% smaller), may show minor image degradation - Medium: Balanced reduction (30-50% smaller), good visual quality for on-screen reading - High: Mild reduction (10-25% smaller), nearly indistinguishable from original
- All processing client-side - no upload
- Visual before/after size comparison
- Quality levels balance size vs. fidelity
- Metadata privacy: removed from compressed file
Worked Example
Example: Compressing a 2-page scanned document with images:
Original file: 1.8 MB (300 DPI images)
- Low quality output: 350 KB (~81% reduction) - Medium quality output: 650 KB (~64% reduction) - High quality output: 1.4 MB (~22% reduction)
The calculator shows the estimated size before you download, so you can choose the level that best fits your needs (email attachment vs. archival quality).
Compression Limits
- Very simple PDFs (text-only, no images) may not compress much further - PDFs already compressed may see minimal additional reduction - Image-heavy PDFs (scans, photographs) see the most significant reductions - The calculator estimates size based on standard compression algorithms; actual results may vary
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Open calculator →Frequently Asked Questions
Will compression affect the readability of text?
At Medium and High quality settings, text remains perfectly crisp. Low quality may slightly blur very small text in highly detailed documents, but is generally fine for reading on screen.
Can I compress a PDF that's already small (under 100KB)?
Yes, but the size reduction will be minimal. The tool will still process the file and return a similarly-sized PDF.
Do compressed PDFs work in all PDF readers?
Yes. The compressed PDF maintains the PDF-1.7 format compatible with all modern readers (Adobe Acrobat, Chrome, Preview, etc.).
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