Split a PDF at its bookmarks

A bookmarked PDF already knows where its chapters begin. The author put that structure in, as a table of contents, an outline pane, the list your reader shows down the side, and splitting on it gives you one file per chapter without anyone having to look up a single page number.

Top level only

Only the outermost bookmarks start a new file. A technical manual with headings nested three deep inside each chapter would otherwise come apart into hundreds of two-page fragments, which is never what anyone means by splitting at the chapters.

So a book with twelve chapters becomes twelve files, whatever is nested inside them. Any pages before the first bookmark, such as a cover, a title page or a foreword nobody bookmarked, become a part of their own at the front rather than being silently attached to chapter one.

When there is nothing to split on

Plenty of PDFs have no bookmarks at all. Scans have none. Exports from word processors often have none unless somebody asked for them. A document assembled by merging others usually loses them.

When that happens the tool says so, and says what to do instead, rather than producing a single file identical to the input and calling it a split. A bookmark pointing at nothing, which happens in documents that have been edited and re-saved, is skipped rather than treated as a chapter boundary at page one.

Nothing is re-rendered

Each chapter is built by copying the original pages into a new document. Text stays selectable and searchable, images are not re-encoded, and vector artwork stays sharp. The chapters together are about the size of the original.

Bookmarks nested inside a chapter travel with its pages. The document-level outline itself does not survive being divided, because it described a document that is now several.

Nothing leaves the device

The document, its outline and its pages are read by a worker inside your browser. There is no upload, no account, and no server copy.