Compress PDF
Compress PDFWhat it's for: shrink a PDF's file size for emailing, uploading, or archiving, without needing to re-export it from the original source app.
- Pick: open a PDF, or drop it anywhere on the window.
- Configure: drag the compression slider (or pick a Quality Preset), optionally turn on Resize pages and/or Remove personal info.
- Compare: see the before/after file size and a page preview before committing.
- Save: write the compressed file to disk.
The slider has four zones, each setting a target resolution and image quality:
| Zone | Preset | Resolution | Best for |
|---|---|---|---|
| Web | screen |
72 dpi | Smallest file, screen-only viewing |
| Screen | ebook |
150 dpi | Balanced: good for reading on devices |
printer |
300 dpi | High quality, suitable for printing | |
| Archive | prepress |
Lossless | No recompression: structural cleanup only |
PaperOtter re-encodes every embedded image at the target resolution/quality for the chosen preset. PaperOtter also shows an estimated output size per zone before you commit, based on how many images the PDF actually contains: a text-only PDF won't shrink much no matter which preset you pick, since there's nothing image-heavy to recompress.
If you turn on Target file size instead of picking a preset directly, PaperOtter tries presets from your starting point down to screen (the smallest), stopping as soon as one hits your target, or keeping the smallest result it found if none do.
- Resize pages: scales page content to a standard size (A4/A3/Letter), or a custom size, centered and scaled to fit. This runs before compression, so it's not undone by the compression step.
- Remove personal info: clears the PDF's title, author, subject, keywords, creator, and producer metadata fields, for GDPR-style data minimization. It does not touch DRM, encryption, or copyright metadata.
- It's already small relative to its content. If the result would be larger than the input — which happens on text-only or already-optimized PDFs, where there is nothing to take away — PaperOtter keeps the original instead. A document with no images is returned byte-for-byte unchanged. You'll see a note that the file was already optimal rather than a bigger "compressed" file.
- Few or no images. Compression here works by recompressing embedded images. A PDF that's mostly text has little to shrink: try a lower preset, but don't expect the same reduction you'd see on a scan-heavy or photo-heavy PDF.
See also: Repair PDF · Required Dependencies