Five ways to split a PDF
Which way fits depends on what you know about the document. You can switch between them at any time, and the list of files updates as you do.
Every page makes one PDF per page. It suits scans, forms where each page goes to a different person, and anything you want to hand out page by page. The page about splitting a PDF into single pages goes into that case.
Every N pages cuts the document into equal groups, such as 10 pages per file. The last file gets whatever is left, so 25 pages in groups of 10 give files of 10, 10 and 5 pages.
Custom ranges takes a list like 1-3, 4-6, 7-. Each range becomes its own file, and 7- means page 7 to the end. Ranges may overlap, which is useful when a cover page belongs in every file. Pages that are in no range are not saved. The tool tells you about both, in words, before you split.
Split after chosen pages is for cutting where you can see the cut. Click the last page of each part in the grid, or type the page numbers, and a scissors mark shows where the document will be cut. Choose page 12 of a 30 page file and you get pages 1 to 12 and pages 13 to 30. A cut after the last page would leave an empty file, so that page cannot be chosen.
By bookmarks makes one file for each top level bookmark and puts the bookmark's title in the file name. It is only offered when the PDF has bookmarks that lead to pages. Sub-bookmarks stay inside the file of their parent. A heading with no target of its own starts where its first sub-bookmark starts, and any pages before the first bookmark become a file of their own unless you switch that off.
What the new files contain
A PDF is a list of pages, and splitting copies the pages you chose into new files. Nothing is redrawn or recompressed: text stays text, photos keep the quality they had, and every page keeps its size, rotation and crop box. A document that mixes portrait and landscape pages stays mixed.
A few things belong to the whole document and cannot follow a page into a new file. Bookmarks, the outline in a viewer's side panel, are not copied. Links that jump to another page of the original are dropped, because their target may now be in a different file. Links to websites, highlights and comments stay on their pages. Form fields keep their look and the values typed into them, but the new file no longer contains a form, so do not count on filling them in. The title, author and other document information of the original are not copied either, and neither are files attached to the document as a whole. A paper clip attachment that sits on a page stays on it.
Every file has to open on its own, so each one carries the fonts and images its pages use. For a scan, where every page is one picture, the files add up to about the size of the original. For a text document that uses one embedded font, every file gets its own copy of it: a 300 page text document of about 240 KB that uses one embedded font gave single page files of about 32 KB each and 9.3 MB together. When the files would add up to more than 100 MB and more than five times the original, ClipLime warns you before you split. When they add up to more than the original, the result card says so. If size matters, compress the files after splitting.
File names and the ZIP
Names start with the name of your file and end with what the new file holds, so they stay recognisable after they leave this page: report-part-1.pdf for equal groups, report-pages-4-6.pdf for ranges and cuts, report-page-5.pdf for a single page, and report-Introduction.pdf for a bookmark called Introduction. Characters that file systems do not allow are replaced with a space, two files never get the same name (the second Summary becomes report-Summary (2).pdf), and a name is never longer than 120 characters.
When there are several files, Download all as ZIP packs them into report-split.zip. The ZIP stores the files as they are, without squeezing them further, which is quick and keeps memory low. Every file can also be downloaded on its own from the list. Browsers often block a page that starts many downloads at once, which is why the ZIP is the main button for more than one file.
Big files and your device
Splitting happens in your browser, so the limit is your device's memory. The file is read once and each new file is built and saved in turn. Plan for about two to three times the size of the PDF in free memory. ClipLime warns you when a file is large for your device, roughly 60 MB on a phone and a few hundred megabytes on a computer, and refuses files above 1 GB.
You can press Cancel while it works. Nothing has been saved by then, and your settings stay as they were, so you can change them and run again. Each finished file is opened again and its pages are counted before you are offered a download.