Why are PDFs so big?
Almost always because of pictures: scanned pages, photos and screenshots saved at far higher resolution than a screen or printer needs. A ten-page scan from a phone can easily reach 20 MB. Text and drawings take very little room.
Two ways to compress
- Keep text (recommended): finds every picture in the PDF and re-saves it at the resolution it is actually shown at. Text, fonts, links and form fields are untouched, so the document stays searchable and sharp. Identical pictures and fonts are stored once, and unused data is removed.
- Smallest file: turns every page into a single compressed picture. This gives the smallest files for scans and photo-heavy documents, but the text can no longer be selected, searched or copied.
How to compress a PDF
- Drop your PDF — compression starts straight away with balanced settings.
- Compare the sizes. If it is still too big, choose Strong, or Smallest file for scanned documents.
- Download the compressed copy. Your original file is not changed.
Good to know
- PDFs that are mostly text are usually small already and may shrink only a little.
- Balanced keeps pictures at about 144 dpi, plenty for reading on screen and for normal printing. Choose Light for documents you will print at high quality.
- Digitally signed PDFs lose their signature’s validity when they are changed in any way, including compression.
- Everything happens in your browser, so confidential documents stay private.
Frequently asked questions
How do I compress a PDF to under 1 MB?
Start with Balanced. If it is still over 1 MB, try Strong, and for scanned documents choose Smallest file, which usually brings a scan down to around 100–200 KB per page or less.
Will compressing reduce the quality?
Text and drawings keep their full quality in the recommended mode. Pictures are re-saved at a lower resolution, which is hard to notice on screen at Light or Balanced.
Is there a file size limit?
No fixed limit. Because the work happens on your device, very large files (hundreds of megabytes) need a computer with enough memory.