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Compress PDF Online

Reduce the file size of a PDF without uploading it anywhere. PDFKat optimises the PDF structure in your browser and offers three compression levels to balance quality and size.

Compression level

How to use Compress PDF Online

  1. 1Upload one PDF file.
  2. 2Choose a compression level: Low, Medium, or High.
  3. 3Select Compress PDF.
  4. 4Download the optimised PDF and compare the file sizes.

Privacy-first processing

Your PDF is compressed locally in your browser. It is not uploaded to a PDFKat server for this tool.

FAQs

How much will the PDF shrink?

Results depend on the PDF content. Documents with unoptimised structure can shrink 5–20%. PDFs with already-compressed images may see little reduction.

Will compression reduce image quality?

Higher compression levels re-encode images at lower quality. Low compression uses lossless structure optimisation only.

Is my PDF uploaded to a server?

No. The compress tool processes your file locally in your browser.

Can I compress a password-protected PDF?

Password-protected PDFs cannot be processed by this browser-based tool. Remove the password first using an appropriate tool.

Related PDF tools

Merge PDFCombine multiple PDF files into one clean document.Split PDFSeparate a PDF into individual page files.PDF to JPGConvert every PDF page to a JPG image and download a ZIP.Extract PagesPick the exact pages you need from a larger file.

Best for quick document work

PDFKat is built for simple everyday PDF tasks on desktop and mobile browsers. For best results, use files that are not password-protected or restricted.