Compress / optimize PDF online
Last updated: August 2026
Quick answer: ScanTo can re-save a PDF with optimized object streams. For photo-based scans, the strongest size reduction is usually Scan to PDF at lower JPEG quality.
Privacy-first: processing stays on your device.
A compressed PDF is easier to email, upload, and archive. The ScanTo compressor works especially well on scans and photo-heavy PDFs — try it first, and only raise the quality setting if the result looks soft on screen.
Frequently asked questions
How do I get the smallest scan PDF?
Photograph or export pages as images, then use Scan to PDF with quality around 60-75%.
Will optimize reduce every PDF a lot?
Text-heavy PDFs may shrink only slightly. Image-heavy scans benefit more from the image workflow.
Is compress PDF free?
Yes, with no account required.
Related tools
Also free: Mind Map Online — create mind maps with no login.