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PDF Compressor

Make a PDF smaller. There are two honest ways to do this, and the right one depends on what is inside your document — the tool offers both and explains the trade-off rather than guessing for you.

PDF Compressor tool

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How to use the PDF Compressor

  1. Add a PDF

    Drop one PDF onto the upload area. Its current size is shown so you have a baseline to compare against.

  2. Pick a compression method

    Re-encode pages rasterises each page as a JPEG — this is what shrinks scans dramatically, but text stops being selectable. Strip metadata only is lossless and leaves the pages untouched.

  3. Adjust quality if needed

    For the re-encode method, lower DPI and quality produce smaller files. 120 DPI at 70% quality is a reasonable starting point for documents meant to be read on screen.

  4. Compress and compare

    Press Compress PDF. The result shows the before and after sizes so you can decide whether to accept it or try different settings.

Where your files are processed

Your files are processed locally in your browser and are not uploaded to our servers.

The PDF Compressor runs as JavaScript on the page you are reading. When you choose a file, the browser hands it to that code directly — it is never put into a network request, so there is no upload to cancel, no copy sitting in a queue somewhere, and nothing for us to delete afterwards. We could not see your file if we wanted to.

You can verify this rather than take our word for it: open your browser’s developer tools, switch to the Network tab, and run the tool. You will see no request carrying your file. Better still, once the page has loaded you can disconnect from the internet entirely and the PDF Compressor will keep working — which it could not do if it depended on a server.

To be exact about what doesleave the page: like the rest of this site, it loads analytics, which record that a tool was opened and whether it succeeded. Those events carry the tool’s name and a duration — never a file, a file name, or anything read out of your file. The tool panel above is also excluded from session recording, so nothing shown inside it is captured either.

Frequently asked questions

Almost certainly because it is a text PDF. Text in a PDF is stored as font instructions and is already extremely compact — there is very little left to squeeze. Compression tools make their dramatic gains on embedded images, so a document that contains none has nothing to give.

Re-encode pages converts each page into a compressed picture of itself. That is why it works so well on scans, and why the text afterwards cannot be selected, searched or copied. Strip metadata only removes document properties and re-saves the file more efficiently — a smaller saving, but completely lossless.

With the re-encode method, at a low enough DPI, yes. That is inherent to turning text into an image. If the document is going to be printed, stay at 150 DPI or higher; for reading on a screen, 120 DPI usually looks fine.

No. Both methods run in your browser — pdf.js renders the pages and pdf-lib rebuilds the file, all locally. The document never leaves your device.

No. The file has to be readable to be compressed, and an encrypted PDF is not. Save an unprotected copy from your PDF reader first.

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Credits

The file-processing behind this tool is adapted from DoxDock by Mithun Srinivas, used under the MIT Licence. Rebuilt here in TypeScript for this site.

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