Compress PDF Size — Offline & Private
Reduce PDF file size for email or sharing. Processed in your browser — your document never leaves your device.
Reduce PDF file size for email or sharing. Processed in your browser — your document never leaves your device.
Cloud compression services scan your document structure on their hardware to optimise it. That's necessary when you don't have a local engine — but it also means your file leaves your machine. OfflinePDF compresses PDFs using the pdf-lib JavaScript library running in your browser tab. The compression rewrites the internal PDF structure: removing redundant objects, optimising cross-reference tables, and shrinking embedded data — without any server involvement.
| Feature | OfflinePDF | Typical Online Tools |
|---|---|---|
| Uploads your PDF | Never | Always |
| Server-side processing | None | Always |
| Works offline | Yes | No |
| Output watermark | Never | Free tiers often add |
| Daily usage limit | None | Typically 2–5 free |
It depends on the source. PDFs with lots of duplicate internal objects compress the most — commonly 20–60%. Image-heavy PDFs may see less reduction since images are already encoded.
This tool focuses on structural compression, not image re-sampling, so visual quality is maintained.
Currently one file at a time. For bulk compression, refresh and repeat.