Compress a PDF, and choose the size
Four sizes, each a finished file
Choose the PDF and the page shows how far along the measuring is: a large scan takes a little while. Then you get up to four cards, largest first. Each is a file already made, not an estimate: its size, how much smaller it is than yours, what it gives up, from nothing you can see to coarse photographs, and the same small piece of a page from your file and from it, side by side at 100% zoom. That piece is the smallest, densest text in the file, so what you look at is the worst of what you give up.
Choose one and it downloads. It is also kept in your documents as a new one, and the file you started from stays as it was.
Why those four
The largest looks the same as your file, on screen and printed. The smallest is the smallest at which every word still reads. The two between are spaced so that each is about the same fraction smaller than the one before, which puts the steps where a difference can be seen instead of three near-copies and one cliff. When there are not four real choices you get fewer: a file that saves less than a tenth, or less than a fifth over the one before it, is not worth a card.
When you need a particular size
An upload form or an email often has a limit of its own. Pick it from the list, from 100 KB to 10 MB and the sizes that fit a Gmail or an Outlook attachment, or type your own, and you get the best-looking file under it.
Compress a PDF now — it opens the tool, with nothing to install.
What it never does
- It never makes a page harder to read to reach a size. Every page of every file it offers is compared with yours at reading size, and a setting that falls below its measured limit for legibility is not offered, whatever size was asked for.
- It never turns text or drawings into pictures. The page images are made smaller and the file's structure is tidied; text stays text, sharp and searchable.
- It never makes an image larger, and never saves one at a higher quality than it already had, which would add bytes and lose detail at once.
When it says no
A file of text and fonts, with few page images, has little to give: the tool says so, and says where its bytes are, rather than offer a file that is barely smaller. A scan already at a low resolution may have no detail left to give without becoming hard to read, and it says that too. A file with a password asks for it. It takes files of up to 100 MB.
The record
The smaller file says how it was made: which setting, the resolution and quality each image was saved at, which images were left as they were, and the sizes before and after. A document you corrected here becomes a new document when it is compressed, because compressing changes the pixels its correction was checked on; the check and the certificate stay with the one you corrected. The sizes made for your file are deleted an hour after they are made, or as soon as you choose one, and the file you choose is deleted after 90 days, or whenever you erase it.