How to compress a PDF
- Drop your PDF into the box or choose it. Several at once work too.
- Pick a level. Medium suits email and most uploads; Strong makes the smallest file, with softer photos.
- Download the smaller PDF. The new size shows next to the file before you download.
Why PDFs get so big
Almost all of a large PDF’s size is pictures. A phone photo or a page scanned at high resolution can hold 10 to 20 million pixels, far more than a screen or even a printer needs at the size it appears on the page. A single such image can be several megabytes, and a scanned document repeats that on every page.
This tool goes through every picture in the file, shrinks the ones that are larger than the level you chose, and saves them as JPEG. Each image is only swapped when the new version is smaller. The rest of the PDF is written back with its structure compressed, which saves a little more.
Common size limits
Many email services cap attachments at around 20 to 25 MB, and online forms, job applications and government portals often accept only a few megabytes. Compress to Medium first and check the size; switch to Strong only if you still need it smaller. For a long document, splitting it into parts is another way to get under a limit without losing quality.