How to compress a PDF
- 1
Add your PDF
Drop a PDF in or click to choose one.
- 2
Pick a compression level
Choose Low, Medium or High depending on how much you want to shrink it.
- 3
Compress & download
Your PDF is rebuilt on your device. Download it once it’s ready.
What is PDF Compression?
PDF Compression reduces the file size of a PDF document so it's easier to email, upload or store — useful when you need to compress a PDF to a specific target like 1MB for an upload form, or shrink a scanned document down to under 100kb for an attachment limit. This tool compresses by re-rendering each page as a JPEG image at a chosen quality and resolution, then rebuilding those images into a new PDF — an approach that works especially well on scanned documents and image-heavy files.
Worth knowing upfront: because every page is converted into an image and reassembled, the text in the compressed PDF is no longer selectable, searchable or copyable — the same honest trade-off our Exam Photo Resizer tool discloses about its HEIC conversion step. This compressor is best suited for cases like email attachments, archival copies or upload-size limits, where how the document looks matters more than being able to select text in the output. If you need to keep an editable text layer, this image-based approach isn't the right tool for that.
Most online PDF compressors require uploading your files to a server, which is a privacy risk for sensitive documents. Tools11x avoids this entirely by rendering and compressing your PDF locally in your browser using a background Web Worker, so the page stays responsive even on large files and your document never leaves your device.
Questions
How does this PDF compressor work?
This tool renders every page of your PDF onto a canvas using Mozilla’s PDF.js, re-encodes each page as a JPEG image at an adjustable quality and resolution, and then reassembles those images into a brand-new PDF using pdf-lib. This image-based approach can dramatically shrink file size, especially for PDFs with scanned pages, photos or heavy graphics.
Will the text in my PDF still be selectable after compressing?
No. Because each page is converted into a JPEG image and then rebuilt into a PDF, the compressed file is entirely image-based — the original text layer is not preserved, so text will no longer be selectable, searchable or copyable. This is expected behavior for this compression method and is best suited for cases like email attachments or archival storage where visual fidelity matters more than editable text.
What is the difference between Low, Medium and High compression?
Low compression keeps a higher resolution and JPEG quality, so pages stay closer to the original but file size savings are smaller. Medium balances quality and size for most everyday PDFs. High compression lowers both resolution and JPEG quality the most, producing the smallest possible file at the cost of visibly softer text and images. Try Medium first, and switch to High if you need the file even smaller.
Are my PDFs uploaded to a server?
No, never. All rendering, compression and reassembly happens locally in your browser using a background Web Worker, so the page never freezes even on large files. Your PDF is never sent anywhere, which keeps sensitive or confidential documents completely private.
Why did my PDF not get much smaller?
If your PDF is already mostly text with little imagery, it may already be small, and converting pages to JPEGs can sometimes add overhead rather than save space. This tool works best on PDFs that are large due to high-resolution scans, embedded photos, or dense graphics. For text-heavy documents where you need to preserve selectable text, a different approach that keeps the text layer intact would be more appropriate.
Is there a file size limit?
There’s no artificial limit imposed by the tool itself — processing happens on your device, so the practical limit is your browser’s available memory. Very large PDFs (dozens of high-resolution pages) may take longer to process, and progress is shown page-by-page so you can track it.