The compressor tries two methods and keeps whichever produces the smaller file: a lossless structural re-save, and re-encoding each page as an optimised JPEG at 80–150 DPI. Scanned documents and image-heavy PDFs usually shrink by 50–90%.
How to compress a PDF
- Choose the PDF you want to shrink.
- Pick a level. Recommended suits most documents; Strong gives the smallest file.
- Press Compress PDF. The smaller file downloads and the saving is shown.
Which level should I choose?
| Level | Page resolution | Good for |
|---|---|---|
| Low | 150 DPI | Printing, documents with small text |
| Recommended | 110 DPI | Email, sharing, on-screen reading |
| Strong | 80 DPI | Upload forms with strict size limits |
Important: selectable text
When image re-compression gives the smallest result, pages become images, so text can no longer be selected or searched. For contracts you need to edit or search later, keep the original as well. If the lossless method wins, the tool tells you and text stays selectable.
Why are scanned PDFs so big?
Scanners often save each page as a full-colour 300–600 DPI image. A page of text only needs about 100–150 DPI to read comfortably on screen, so most of that data can be removed safely.
Frequently asked questions
How much can a PDF be compressed?
Scanned and photo-heavy PDFs often shrink by 70–90%. PDFs that are mostly text from Word are already small and may shrink only a little.
Can I compress a PDF to under 1 MB or 200 KB?
Usually yes with the Strong level. If it is still too large, split the PDF and send it in parts, or remove unneeded pages.
Will the compressed PDF look blurry?
At the Recommended level text remains clear on screen. Choose Low for documents with very small print.
Are my PDF files safe?
Yes. The PDF is read and written by JavaScript libraries (pdf-lib and Mozilla pdf.js) inside your browser. The file is never uploaded, so confidential contracts, bank statements and ID scans stay on your device.
Updated October 2026 · Built and tested by Sharjeel Tahir · How our tools are tested