How to split a big PDF into chapters or sections

To split PDF into multiple files by chapter or section, open our free Split PDF tool, choose Custom ranges and type one page range for each part, such as 1-12 | 13-40 | 41-. Each range becomes its own PDF, and all of them download together as one ZIP. Nothing is uploaded: the document is split by your own browser, and every page keeps its original quality.

The one thing the tool can't do for you is find the chapters. It does not read bookmarks or headings, so you first note the page where each chapter starts. This guide shows how to do that quickly and how to check the result before you download.

Step 1: find where each chapter starts

You need the file's page positions, counted from the very first page of the PDF as page 1. Three easy ways to find them:

• The bookmarks panel. Many books and reports have an outline in a PDF reader's sidebar. Clicking a chapter there jumps to it and shows its page position in the page box.
• The contents page. It lists the printed page numbers. These are often different from the file positions, because a cover, a title page and front pages numbered i, ii, iii come first. Find chapter 1 in the file and work out the difference: if printed page 1 is file page 9, every chapter starts 8 pages later than the contents page says.
• The thumbnails in Split PDF. Each thumbnail is labelled with its file position, so you can scroll and look for the chapter title pages.

Write the start pages down, for example: chapter 1 at 9, chapter 2 at 31, chapter 3 at 58, references at 90.

Step 2: split PDF into multiple files with custom ranges

1. Open your file in Split PDF. PDFs of up to 200 MB can be opened.
2. Choose Custom ranges in the Split mode row.
3. Type one range per part, separated by | or on separate lines. Each part runs from its chapter's start page to the page before the next one:

1-8
9-30
31-57
58-89
90-

4. Check the badges. Each thumbnail now shows a small #1, #2, #3 badge telling you which file that page will go into. Scroll through and make sure each chapter's first page carries the new number.
5. Click Split into 5 PDFs, then Download ZIP. You can also download any single part from the list.

The parts are named after the original, numbered in order, with their page range: thesis-1-pages-1-8.pdf, thesis-2-pages-9-30.pdf and so on. Like every download from our site, the names begin with "Tech Solution Point - ".

Range tricks worth knowing

You type	You get
1-12 | 13-40 | 41-	Three files; 41- runs to the last page
1, 9-30 | 1, 31-57	Page 1 (a cover) at the start of both files
9-30 | 31-57	Only chapters 1 and 2; the other pages are left out
9-29, 31-57 on one line	One file without page 30 (a blank page, say)

Pages inside one file always stay in their original order. Commas add pages to the same file; only | or a new line starts a new file.

Equal parts: every N pages

Some documents don't have chapters, just a lot of pages: a year of bank statements, a long scan, a question bank. For those, choose Every N pages and type a number. A 100-page file with 25 becomes four 25-page files; if the count doesn't divide evenly, the last file is shorter. The tool shows how many files you will get as you type.

A visual way: new part at each selected page

If you would rather click than type, open your file in PDF Studio and go to the Pages tab (called Organize pages in the Advanced view). In the Split panel, set Split into to New part at each selected page. Select the first page of each chapter, click Split and download (ZIP), and every selected page starts a new part (the first part always begins at page 1). The parts are named -part-1.pdf, -part-2.pdf and so on. PDF Studio is a full editor, so it is the better choice if you also want to rotate, delete or add pages first.

Splitting to meet an upload size limit

Portals for job, visa and university applications often cap each file's size. Split PDF cuts by pages, not by megabytes, so:

1. Split into parts with Every N pages or your own ranges.
2. Look at the Size column in the list of results.
3. If a part is still too big, split it into smaller ranges or run it through Compress PDF. Our guide on compressing a PDF to under 1 MB explains the settings.

Note that the parts can add up to more than the original size. Pages share fonts and images, and each new file must carry its own copy of what its pages use.

What is kept in each part

Pages are copied, not redrawn, so text stays selectable, images keep their quality, and page sizes and rotation are unchanged. Bookmarks are not copied into the new files, so a part won't have the original's sidebar outline.

Common problems

A chapter starts one page too early or too late

This is almost always the gap between printed numbers and file positions. Go by the thumbnail labels and the badges, then adjust the ranges.

"Range 2: … is outside 1–120"

A range goes past the last page. The message names the range, so fix that one, or end the last range with a dash (90-) so it always runs to the end.

The PDF won't open

If it is password-protected, remove the password with PDF Unlock first. If the parts need to be rejoined later, use PDF Merge; see how to merge PDFs without uploading.

For a single page or every page on its own, see extracting one page and saving every page as its own file.

Quick checklist

• Chapter start pages noted as file positions, not printed numbers
• One range per part, separated by | or new lines
• Badges checked on the thumbnails before splitting
• Sizes checked in the results list against any upload limit
• Parts opened and checked before sending