Scanned PDF Optimization Benchmark.
| Document | Format & Size |
|---|---|
| Input File Type | Scanned PDF / Image-Based PDF |
| Image Downsampling Target | 150 DPI – 200 DPI Grayscale/Color |
| Average Size Reduction | 60% to 90% Compression Ratio |
| Processing Speed | < 3 Seconds via WebAssembly |
Last verified: August 2026
Why scanned PDFs are so huge.
Physical documents scanned with home scanners or smartphone scanner apps capture millions of raw pixels per page. A single color scan at 600 DPI can produce a 5 MB to 10 MB file for just one page.
Zcompressor analyzes the image stream resolution, downsizes bloated raster dimensions, and applies efficient JPEG stream encoding to compress scanned PDFs rapidly.
Your files stay on your device.
Your scanned physical certificates and personal contracts never leave your screen.
Frequently Asked Questions.
Yes! Zcompressor processes multi-page scanned documents page by page in parallel WebAssembly threads without page count limits.