Splitting turns one document into many. The common reason is that something downstream wants the pages separately — an upload form that takes one document at a time, a filing system expecting one record per file, or a colleague who needs chapter three and nothing else.
Every page, or groups of them
Setting pages-per-file to 1 gives you one PDF for every page, which is what most people want. Larger numbers group them: 2 turns a 40-page document into 20 two-page files, which suits documents where each record spans a known number of pages — invoices with a covering sheet, or forms with a continuation page.
Output files are numbered with leading zeros — 01, 02 … 10 rather than 1, 2 … 10 — so they sort correctly in a file manager. Without the padding, page 10 sorts before page 2, which is a small thing that causes a surprising amount of trouble when the files are later re-merged.
If you want specific pages, do not split
Splitting produces every page as a separate file, which is a blunt instrument if you only wanted pages 4 to 9. The page extractor takes a range and gives you a single document containing exactly those pages, which is almost always what people mean when they say they want to "split out" a section. Use this page when you genuinely want the whole document broken apart.
Lossless, like every page operation here
- Pages are copied, not re-drawn. Text stays selectable and searchable.
- Embedded images keep their original bytes, so scans do not soften.
- Vector content stays vector, so it prints at full resolution.
- The pieces total roughly the size of the original, sometimes slightly more — each file has to carry its own copy of any font it uses.
Downloading many files at once
A 50-page document produces 50 downloads. Your browser will ask once whether to allow multiple files, and they are then triggered one at a time with a brief pause between them, because browsers throttle or silently drop rapid bursts. There is no zip option: building one would mean holding every output in memory simultaneously, which is exactly the pressure that processing them one at a time avoids.
Encrypted PDFs are refused with an explanation rather than a stack trace — remove the password in a reader first. Everything runs in this tab, with nothing uploaded.
Think about what happens to the pieces
Fifty separate files are harder to handle than one document, so it is worth being sure that is what the destination needs. If you are splitting only to email a section, extract those pages instead. If you are splitting to upload one page at a time, check whether the form accepts a multi-page document first — many do, despite what the instructions suggest.