Compress PDF — Reduce File Size Online for Free
Shrink PDF size by compressing embedded images. Works best on image-heavy PDFs.
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🔐 Your files never leave your session — auto-deleted in 60 min
What do you need to do next?
Frequently Asked Questions
How does PDF compression work?
ZillyPDF compresses PDFs by rasterising each page through Imagick and re-encoding at a lower JPEG quality. This works best on image-heavy PDFs and scanned documents. If your PDF contains mostly text or is already optimised, the tool will let you know it cannot reduce the size further.
Will compression affect text quality?
Because compression works by converting pages to images, both text and graphics are rendered at a lower resolution. For best results use this tool on scanned documents or image-heavy PDFs rather than text-only documents.
What compression level should I choose?
“Medium” is recommended for most use cases — it balances file size reduction with acceptable image quality. Choose “High” if you need the smallest possible file and can accept lower image quality.
Is there a file size limit?
Yes, 50MB per file. Files are automatically deleted after 60 minutes.
Are my files kept private?
Yes. Your files are processed securely and never shared. All files are automatically and permanently deleted after 60 minutes.