Why PDFs get so big
Most PDF weight is images: scanned pages, embedded photos, background graphics. A scan of one page can weigh more than a hundred pages of pure text.
Compression attacks that bulk two ways: tidying the file's internal structure (lossless) or recompressing the images themselves (lossy, but dramatic).
Picking a compression level
Start lossless for digital documents — contracts, reports, exports. It reorganizes the PDF without touching content: text stays text, links stay links.
For scans hitting a hard size cap, image-based compression trades sharpness for size. 'Recommended' usually halves the file while staying readable; 'extreme' is for brutal limits.
| Method | How it works | Effect on image quality |
|---|---|---|
| Lossless | Reorganizes the file structure and removes unused data | Preserves visible content |
| Image compression | Recompresses images to reduce file size | May reduce sharpness; preview the result |
When compression isn't enough
If a PDF is still too large, ask whether all of it needs to go: Split PDF or Extract Pages can send only the relevant portion.
For scans that will mostly be searched rather than viewed, OCR the file first — text layers compress far better than images.
