Three modes, sensible default
Recommended balances size and quality for any document. Strong squeezes scans hardest, and Lossless changes nothing but the file structure.
Compress PDF online — free and private
Compress PDF reduces the size of your PDF so it is easier to email, upload or archive. Recommended mode gives you the best balance automatically: it rebuilds the file with maximum stream compression, keeps text crisp and selectable, and re-encodes scanned pages only when that actually helps. Choose Strong for the smallest possible scan, or Lossless to touch nothing but the file structure.
As with every PDF10x tool, compression runs completely inside your browser. Your file is never uploaded, which means no privacy risk and no waiting for large uploads and downloads. For very large documents, splitting the file first with Split PDF and compressing each part can help too.
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Why use PDF10x to compress pdf?
Never bigger than you started
Every mode is compared against your original file and the smallest result wins, so compressing can never hand you back a larger PDF.
Private and instant
No upload queue, no server. Compression starts immediately on your device and your document stays yours.
How to compress pdf online
- 1
Select or drop the PDF you want to compress.
- 2
Keep Recommended, or pick Strong for scans and Lossless to preserve the file exactly.
- 3
Click “Compress PDF” and watch the size drop.
- 4
Download the compressed file and check the size savings.
Frequently asked questions
Which compression mode should I choose?
Start with Recommended — it handles both text documents and scans sensibly and never damages selectable text. Pick Strong when you need the smallest possible file from a scan or photo-heavy PDF and do not need to copy the text. Pick Lossless when the file must stay byte-for-byte faithful in content and only the structure may change.
Why did my PDF barely shrink?
Text-based PDFs are already very compact — a page of text can be just a few kilobytes — so there is little to remove beyond structural savings. Big reductions come from documents whose size is mostly scanned images. If your file is a text document that is already well optimized, no tool can shrink it much without turning the text into pictures.
Can compressing make my file bigger?
Not here. Every mode compares its result against your original and returns the smaller of the two, so you never end up with a larger file than you started with.
Does compressing remove anything from my document?
Recommended and Strong remove the invisible bookkeeping a PDF carries: XMP metadata and the accessibility structure tree that screen readers use. Your pages look and print exactly the same, and the text stays selectable, but that hidden data is a large part of many generated PDFs. If you need tagging or metadata preserved, use Lossless mode, which only changes how the file is packed.
Does Strong mode change my document?
Strong mode re-renders each page as an optimized image. The document looks the same, but text is no longer selectable. Keep the original if you need to copy text later.
Is there a file size limit?
There is no hard limit. Processing happens on your device, so very large files are limited only by your browser's available memory.