How does the PDF compressor reduce file size? +
The tool uses pdf-lib to re-save your PDF with object stream optimization. This consolidates redundant internal structures, removes unused objects, and applies cross-reference compression — reducing file size without altering the visible content of the PDF.
How much file size reduction can I expect? +
Typically 10–40%, depending on how the original PDF was created. PDFs exported from design tools like Adobe InDesign or Canva often have unoptimized object structures and compress well. Scanned PDFs (images inside PDF) and already-optimized PDFs will see less reduction.
Is my PDF uploaded to a server? +
No. The entire process runs in your browser using the pdf-lib JavaScript library. Your PDF file never leaves your device and is never transmitted over the internet. This makes the tool safe for confidential documents.
Will compression affect the text or images in my PDF? +
No. This tool only optimizes the internal PDF structure — it does not downsample images, alter fonts, or change any visible content. The compressed PDF will look identical to the original.
Why does it say "already optimized"? +
If your PDF was already saved with object stream compression (e.g., exported from a modern PDF generator), our tool cannot compress it further using this method. In that case, try using a server-side tool, or reduce the embedded image resolution using a tool like Adobe Acrobat's "Reduce File Size" feature.