How PDF compression works
Compression is a set of trade-offs aimed at a size target. Understanding the levers helps you pick Preserve, Balanced, or Strong without myth.
Drop up to 20 PDFs here
Max 150 MB per file · 500 MB total
Files are scanned before analysis.
Target
Mode
Image recompression and downsampling
Most savings come from recompressing page images and reducing resolution where detail is not needed for the use case.
Object cleanup
Unused resources and redundant objects can be dropped when safe. This helps digital PDFs more than photo-only scans.
Rasterisation
When structure cannot shrink enough, pages may be flattened to images. That can hit a tight limit but may reduce text selectability.
Preserve / Balanced / Strong
Preserve leans toward keeping structure. Balanced seeks a compromise. Strong prioritises fitting the target when milder modes cannot.
FAQ
- Do you disclose every engine step?
- We describe the product behaviour users need. Internal engine details stay implementation-private.