Compress PDF
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- 100% Free
- Zero Server Data
A scanned PDF is almost entirely photographs, so making one smaller means re-compressing those and leaving everything else alone. Choose a quality, optionally cap how large the pictures may be, and the panel reports what it saved before you download anything. If a file has nothing worth compressing, it says so rather than handing back the same file with a new name.
1 · Your PDF
2 · How hard to squeeze
Scans of text survive 60 to 75. Photographs you still want to look at want more.
A phone photograph in a document is often four times the size it will ever be viewed at. Capping it saves more than quality does.
Frequently asked questions
Is my document uploaded?
No. Your browser reads the PDF, decodes each photograph, encodes it again and writes a new file, all locally. The site’s security policy sets connect-src ‘none’, so the browser blocks network requests from these pages, meaning the document could not be sent even if the code tried.
Why did nothing happen to my file?
Because there was nothing to compress. A PDF of text is already small: the letters are instructions, not pictures. The size of a PDF is almost entirely the photographs inside it, so a document without any cannot be made meaningfully smaller by any tool, whatever it claims.
Which images get re-compressed?
The ones already stored as photographs. Those are scans and camera pictures, which is exactly what re-encoding helps. Images stored losslessly are screenshots, diagrams and line art, where converting to a photograph format makes a bigger file that looks worse, so they are left alone. The panel reports how many of each it found.
What about pictures with transparency?
Left alone. The transparency is stored in a separate object whose size has to match the picture, and changing one without the other gives the image someone else’s holes. Getting that right is worth doing, but not worth guessing at.
Does capping the size help more than quality?
Usually, yes. A phone photograph dropped into a document is often four times larger than it will ever be displayed, and halving its width removes three quarters of the pixels. Quality reduces the cost of each pixel; the cap reduces how many there are.