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KitWren

PDF Compressor

Reduce PDF file size by recompressing images while keeping text sharp — free, private and in your browser.

  1. Choose your PDF — or drag it onto the box
  2. Pick your options
  3. Download the result
Runs in your browser. Your data and files never leave your device.

About the PDF Compressor

Make PDFs small enough for email attachments, upload forms and portals. The compressor shrinks the photos and scanned images inside your PDF while leaving text and vector graphics untouched, so documents stay crisp and searchable.

For scanned documents, the “Scanned document” option converts each page to a compressed image for the smallest possible file.

Your PDF is compressed in your browser — it is never uploaded.

How does the PDF Compressor work?

Most of a large PDF’s size is usually images. Each JPEG image is decoded, scaled down if it’s higher resolution than needed, and re-encoded at the quality level you choose. Images that wouldn’t get meaningfully smaller are left alone.

The document is then rewritten with compressed object streams, which trims a little more. If the result isn’t smaller than your original, you get the original back.

Tips

  • “Recommended” suits most documents. Try “Strong” if you need to get under an upload limit.
  • PDFs made mostly of text are already small and won’t shrink much.

Guides

Frequently asked questions

Will compression reduce quality?

Images are slightly softened at stronger settings; text and line drawings aren’t affected. Use “Light” if image quality matters most.

Why didn’t my PDF get smaller?

It may already be compressed, or contain mainly text, vector graphics or image types that can’t be recompressed safely. Try the “Scanned document” option for scans.

Can I compress a password-protected PDF?

Unlock it first with the PDF Unlocker, compress it, then protect it again if needed.

Is my PDF uploaded to a server?

No. The PDF is processed by your browser on your own device and never leaves it. Closing the page discards everything.

Is there a file size limit?

Files up to 200 MB are accepted. Very large documents depend on your device’s memory; on phones, files under about 50 MB work best.