PDF compression is a balance between smaller files and readable content. The best setting depends on whether the document contains text, scanned photographs, diagrams or print-quality artwork.
Use the free Compress PDF tool while following the examples below.
What makes a PDF large
High-resolution images, embedded fonts, duplicate resources and scanned pages can increase file size. Text-only PDFs are often already compact.
A scan at print resolution can be many times larger than a digitally generated document with the same number of pages.
Choose compression by purpose
For email and online forms, moderate image compression is usually acceptable. For legal archives, design proofs and printing, preserve more detail.
Always compare small text, signatures and diagrams before deleting the original file.
When compression has limited effect
A PDF may already contain optimized images or compressed streams. Recompressing it can produce little improvement or even increase the size.
If the file remains large, consider removing unnecessary pages or using lower-resolution source images.
Practical checklist
- Work from an accurate original value or source file.
- Review the selected settings before processing.
- Check the result instead of assuming it is correct.
- Keep the original until the new result has been verified.
Frequently asked questions
Does compression remove text?
A good compression process should preserve text, but scanned text is part of an image and can become blurry at aggressive settings.
Can a PDF be compressed repeatedly?
Repeated lossy compression can reduce quality. Work from the original whenever possible.
What is the safest workflow?
Create a compressed copy, compare it with the original and keep both until the new file is accepted.
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Last reviewed: November 11, 2026.