Free Online Compress PDF Tool

1. Upload the PDF you want to shrink.
2. Click Compress PDF to re-write it with object streams and stripped metadata.
3. Compare the original, compressed and saved figures shown.
4. Download the compressed file if it is smaller than the original.

PDF files can be larger than they need to be: loose internal structure, duplicated objects, and bulky metadata all add bytes. The PDF standard (ISO 32000) supports object streams and cross-reference streams, a compact way of packing many small objects together, plus Flate (zlib) compression on content. Re-writing a file with these features turned on can recover meaningful space.

This tool loads your PDF with pdf-lib and saves it again with object streams enabled, while clearing document metadata such as title, author and producer strings. The process is lossless: it does not re-encode images, so photos and graphics keep their exact quality. That makes it safe for documents where fidelity matters, though it means heavily image-based scans may shrink little, since their bulk is in the images themselves.

The tool reports the original size, the compressed size and the percentage saved so you can judge the result. An already-optimised PDF may not get smaller — and that is expected. Everything runs locally; your file is never uploaded.