To compress a PDF, drop it on the box above. Balanced is chosen for you and usually cuts a PDF full of photos or scans to a fraction of its size. Press the download button next to the file when it is done. If the result is still too big for the form or email you are sending it to, pick Strong or Smallest and the file is compressed again.
Why some PDFs are so large
Text barely adds to a PDF's size. A 40 page report with no pictures is often well under 1 MB. The size comes from images: phone photos dropped into a Word file, pages from a scanner saved at high resolution, or slides exported with full size pictures. A single photo from a recent phone can be 3 to 5 MB, and a PDF stores it at that size even when it is shown as a small picture on the page.
That is why this tool works on the images. It finds every photo inside the PDF, scales down the ones that are larger than a page needs, and saves them again as JPEG at a sensible quality. Everything else in the file stays as it was.
The three levels
| Level | What it does | Good for |
|---|---|---|
| Balanced | Photos are limited to 2000 pixels on the long side and saved at quality 72 | Most documents, reports and scans you still want to print |
| Strong | Photos are limited to 1300 pixels and saved at quality 50 | Upload forms with a 1 or 2 MB limit, reading on screen |
| Smallest | Every page is redrawn as one image at 110 DPI | Scanned forms that must fit a very small limit |
With Balanced and Strong the text, lines and shapes in your PDF are untouched, so text stays sharp at any zoom and you can still select, search and copy it. Links, bookmarks and form fields stay too. Smallest turns each page into a picture, so text can no longer be selected or searched. Use it when the size limit matters more than that.
What gets smaller and what doesn't
- Scanned documents and PDFs full of photos shrink the most, often by 70 to 95 percent.
- Charts, diagrams and screenshots stored in a lossless format are left alone at Balanced and Strong, because saving them as JPEG would blur lines and lettering.
- A PDF that is mostly text is already small. The tool tidies its structure, and if that doesn't help you get the original back unchanged.
- Photos stored in CMYK for professional printing are skipped, so their colours don't shift.
If a compressed file comes out larger than the original, you always get the original instead.
Common size limits
Gmail won't attach files over 25 MB, and many job portals, university applications and government forms accept PDFs of only 1 or 2 MB. Try Balanced first and check the size shown next to the file. Strong is usually enough for a 2 MB limit. If a scanned form still won't fit, Smallest almost always gets it there, and you can also remove pages you don't need with Split PDF before compressing.
Signed PDFs
If a PDF carries a certificate-based digital signature, any change to the file makes that signature show as invalid, and compression is a change. The tool warns you when it sees one. Compress the document before it is signed, or send the signed original as it is.
Your files stay on your device
Compression runs in your browser tab. The page downloads the PDF reading code the first time you use it, and your PDF is never sent to a server, which matters for contracts, bank statements and ID documents. Our guide to whether online file converters are safe shows how to check this with your browser's Network tab.
To put several PDFs into one, use Merge PDF. To shrink photos before they go into a document, use the Image Compressor, or Compress Image to KB when a form gives you an exact limit.
