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PDF Compressor

Reduce a PDF's file size by recompressing the color photos and scans embedded inside it. Everything happens in your browser — the PDF is never uploaded.

Runs in your browser — files never leave your device

Free · No sign-upOutputs PDF
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How to use Compress PDF

  1. Add the PDF you want to shrink.

  2. Choose a compression quality — 75-80% is a good starting point.

  3. Click Compress PDF and review how many images were compressed.

  4. Compare the before and after size, then download.

About this tool

A PDF's size is almost always driven by the images inside it rather than its text. This tool scans every page for embedded color photos and scans, re-encodes each one at a quality level you choose, and rebuilds the PDF with the smaller versions — only keeping a change if it's actually smaller than the original. It tells you exactly how many images were found and how many were compressed, rather than implying every PDF will shrink.

This works on the most common case: full-color JPEG images embedded in the PDF, which is how most scanned color documents and photo-heavy reports are stored. Black-and-white scans, images already using lossless compression, and a few less common color formats are deliberately left untouched — attempting to recompress those safely isn't possible with a browser-based approach, and leaving them alone is better than risking a corrupted page.

Common ways people use this

  • Shrinking a scanned color document or report so it fits under an email attachment limit
  • Reducing the size of a photo-heavy PDF (like a portfolio or property listing) before sharing it
  • Getting a large PDF small enough to upload to a portal with a strict file size cap

Tips for better results

  • Check the summary after compressing — it tells you how many images were actually compressible. If it says 0, your PDF likely contains grayscale scans or already-optimized images, and splitting or re-scanning at a lower resolution may work better instead.
  • Try 75-80% quality first. If the size saving isn't enough and the pages still look correct, you can run the compressed result through again at a lower setting.

Frequently asked questions

Why didn't my PDF get any smaller?
This tool recompresses full-color JPEG images embedded in the PDF, which is the most common case. If your PDF is a black-and-white scan, already uses efficient compression, or is mostly text, there may be nothing safe to compress — the summary will show 0 images compressed rather than force a change.
Will this affect the quality of my document?
Only the embedded photos are re-encoded, at a quality level you choose, the same trade-off as compressing a JPEG image directly. Text and vector content are never touched.
Is it safe to compress a scanned contract or ID?
Yes — the file never leaves your browser at any point, the same as every other tool on this site. Nothing is uploaded during compression.
Why do some images get skipped even though the PDF clearly has photos?
This tool only recompresses standard full-color (RGB) JPEG images, which covers the large majority of scanned and photo-heavy PDFs. Grayscale scans and certain less common color formats are intentionally left unchanged, since compressing them safely isn't possible with this approach — leaving them untouched is safer than risking how the page renders.
Can password-protected PDFs be compressed?
No. An encrypted PDF can't be read without its password, so it can't be processed here. Remove the password in the application that created the file first.

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