About this tool
Many websites refuse attachments above 2 MB or 5 MB, and large PDFs are slow to send on mobile data. PDFly offers three levels. Basic compression rewrites the file structure without touching content, so text stays selectable and quality is identical. Medium and Strong compression re-render each page as an optimized JPEG image, which dramatically reduces the size of scanned documents and photo-heavy files.
If the compressed version would be bigger than the original (it happens with files that are already optimized), PDFly keeps your original instead so you never download a worse file.
How to compress a PDF
- 1
Add your PDF
Select the file you want to shrink.
- 2
Choose a level
Basic keeps text selectable. Medium or Strong gives the smallest size for scans.
- 3
Compress
Press “Compress PDF” and wait a few seconds.
- 4
Check and download
The new size and percentage saved are shown before you download.
Questions about Compress PDF
Which level should I choose?
Start with Basic for text documents. For scanned pages or photos, Medium usually gives the best balance between size and readability.
Why can't I select text after Strong compression?
Medium and Strong turn each page into an image. Use Basic if you need searchable text, or run the result through our OCR tool.
How much smaller will my file be?
Scanned documents often shrink by 50–90% with Medium or Strong. Text-only PDFs that are already optimized may only shrink a little.
Related tools
📖 Helpful guides
How to Compress a PDF Without Losing Quality
Why PDFs get large, which compression method to choose, and how to shrink a file while keeping it readable.
How to Reduce PDF Size for Email and Online Forms
Attachment limits explained, plus six practical ways to get a PDF under 2 MB, 5 MB or any size you need.
How to Scan Documents With Your Phone and Save Them as PDF
Take clean photos of paper documents and turn them into a single, light PDF ready to send.
PDFly has 21 free tools for PDF files and images.