How to use Compress PDF
- Select your document in the PDF file field.
- Leave Clear document information unticked unless you want the title, author and producer entries removed.
- Select Optimize and wait for the rebuild.
- Compare the original and rebuilt sizes in the result.
- Download the file ending in -optimized.pdf.
Example: Compress PDF
Rebuild a two-page PDF whose writer stored its objects without compression.
Options
- Clear document information
- Removes the title, author, subject, keywords, creator and producer entries. In this mode the rebuilt file is returned even when it is not smaller, so the entries really are gone.
Supported inputs and limits
Where your input is processed
This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.
Why a structural rebuild rarely shrinks a scan
Almost all the bytes in a scanned PDF are the page images, stored as JPEG or as compressed image streams. A structural rebuild leaves those streams alone, so the only bytes it can reclaim are the overhead around them: the cross-reference table and the way objects are written. On a scan that saving is small, and sometimes it is zero. A text PDF written without object compression may have more structural waste to reclaim. To make a scan much smaller, the images themselves have to be re-encoded or downsized, and that changes how the pages look.
Questions about Compress PDF
Why did my PDF not get smaller?
There was no structural waste to reclaim. Scanned pages are already stored as compressed images and current writers store objects compactly, so the rebuild matches or exceeds the original and the tool hands your file back untouched.
Does compressing change how the pages look?
No. Page content is not re-encoded and only the surrounding structure is rewritten, so the text, images and vector drawing keep their original data and the pages look the same. Compare the two sizes and the page counts to confirm.
Why was my signed PDF refused?
A digital signature is calculated over the exact bytes of the file, so any rewrite breaks it. Rather than return a document that claims to be signed and is not, the tool refuses and leaves your file alone.
When is Clear document information worth using?
When you are about to send a file and its title, author, creator or producer entries reveal something you would rather not share. It is off by default because clearing those entries is a real change to the document.