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PDF Bookmark Generator

Give long PDFs a navigation panel. The generator finds headings by their larger or bold text and turns them into a nested list of bookmarks you can edit, or you type the outline yourself – one line per bookmark with its page number, indented for sub-levels. The result is a real PDF outline that every reader shows in its bookmarks panel.

  • Files stay on your device
  • No sign-up
  • Free to use

How to use PDF Bookmark Generator

  1. Drop a PDF onto the page.
  2. Click “Detect headings” or type bookmarks as Title | page.
  3. Indent lines with two spaces to nest them.
  4. Add the bookmarks and download the PDF.

PDF Bookmark Generator features

Heading detection

Ranks the three largest heading sizes into levels.

Simple editing

Plain text: Title | page, indentation for levels.

Nested outline

Any depth, collapsed under their parent.

Per-page option

One bookmark for every page.

Opens with panel

Optionally shows the bookmarks when the file opens.

Unicode titles

Accented and non-Latin titles are stored correctly.

When to use PDF Bookmark Generator

  • Making scanned reports and manuals navigable.
  • Adding chapters to e-books and theses.
  • Restoring bookmarks lost after merging PDFs.
  • Structuring long contracts and specifications.

PDF Bookmark Generator FAQ

How are headings detected?

The tool measures the size of every line of text. The most common size is body text; larger or bold short lines are heading candidates, and the three largest sizes become levels 1 to 3.

What if detection finds nothing?

Scanned PDFs have no text layer and some documents use one size throughout. Type the bookmarks yourself, or run PDF OCR first.

What happens to existing bookmarks?

They are replaced by the new outline. The tool tells you when the PDF already has bookmarks.

Where does a bookmark jump to?

To the start of its page, fitted to the window.

Do bookmarks change the pages?

No. They are navigation data stored alongside the pages.

Is my PDF uploaded?

No. It is processed in your browser.

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PDF bookmarks and outlines

A PDF outline – shown as bookmarks in Acrobat, Preview, Edge and most other readers – is a tree of titles that jump to places in the document. For long documents it is the quickest way to navigate, far easier than scrolling or searching. Many PDFs lack one because the program that created them did not export headings, or because pages were scanned or merged.

Detection uses the text layout. Headings are usually set larger or bolder than body text, so the tool finds the dominant body size, collects shorter lines that are clearly bigger or bold, and assigns levels by size. The suggestions appear as editable text, because automatic detection cannot know which bold line is a real section.

The text format is deliberately simple: one bookmark per line, the title, a vertical bar and the page number, with two spaces of indentation per level. Bookmarks that skip a level are attached to the nearest possible parent so the outline stays valid.

The outline is written as standard PDF objects with pdf-lib. Titles are stored as Unicode text, children start collapsed, and the document can be set to open with the bookmarks panel visible.

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