Compress a PDF
Make a PDF smaller without uploading it. Ordinary documents are compressed losslessly; scans can be shrunk much further.
- Runs on your device — the file is never sent anywhere
- No sign-up, no watermarks, no daily quotas
- Free, with no limit on how often you use it
How it works
There are two very different ways to make a PDF smaller, and the right one depends on what is inside it. A document exported from a word processor is mostly text and vector graphics: it can only be made smaller losslessly, and the savings are usually modest. A scanned document is a stack of photographs: compressing those images is where the big savings are. Automatic mode looks at your file and picks the method that suits it.
Lossless compression, for ordinary documents
The document's internal structure is rewritten more compactly: objects are packed into compressed streams and existing compression is redone at the highest setting. Nothing about the content changes — text stays selectable and searchable, and every image and font is exactly as it was. Typical savings are a few percent to a few tens of percent. If the file is already stored efficiently, you get your original back rather than a file that is no better.
Image compression, for scanned PDFs
Each page is rendered at the resolution you choose and stored as a compressed JPEG. For a scan, where every page was already a photograph, this is exactly the right operation and the saving is often dramatic. 120 dpi is readable on screen and a good default for archiving; 150 to 200 dpi keeps small print legible for printing. Greyscale roughly halves the size again on a black-and-white scan.
Why image compression is wrong for ordinary PDFs
A PDF exported from a word processor contains real text, which is tiny and infinitely sharp. Turning it into images makes it blurrier, unsearchable, and often larger rather than smaller. Automatic mode never does this to a document with real text, and if you choose the image method yourself on such a document, the result tells you.
Honest limits
Lossless mode does not downsample the images inside a PDF or remove embedded fonts, which is where desktop tools find extra savings on image-heavy documents. Pages are handled up to the site's page limit, and everything happens in your browser, so very large files depend on your device's memory.
Compress a PDF — questions
Will this work on any PDF?
Yes. Ordinary documents are compressed losslessly, so nothing about them changes. Scans are compressed as images. Password-protected PDFs need the password removed first.
How much smaller will my PDF get?
For a text document, usually a modest amount, because text is already compact. For a scanned PDF, often dramatically: 120 dpi greyscale is typically a fraction of a 300 dpi colour scan.
Will the text still be searchable?
With lossless compression, yes — nothing changes. With image compression, no; but a true scan was never searchable either. To get searchable text from a scan, use the scanned PDF to text tool.
Is my document uploaded?
No. It is compressed in your browser.