# PDF Outline

Show the bookmarks of a PDF as a clear table of contents with our PDF Outline tool. It reads the outline that viewers display in their sidebar and returns it as an indented list with the page number each bookmark opens, including nested chapters and links to web pages. Handy for reviewing long reports, manuals, books and theses, checking that every bookmark points to the right page or copying a contents list.

## Frequently asked questions

### What is a PDF outline?

The outline, also called bookmarks, is the clickable table of contents that PDF viewers show in their sidebar. Each entry has a title and usually jumps to a page, and entries can be nested to show chapters and sections.

### How do I see the bookmarks of a PDF?

Upload the PDF and click Show Outline. You get an indented list in which each level of nesting is indented further and every bookmark shows the page it opens.

### How are page numbers determined?

The tool resolves each bookmark destination, including named destinations, to the physical page it opens, counting from 1 for the first page. These numbers can differ from the page labels printed on the pages, such as roman numerals in a preface.

### Why do some bookmarks have no page number?

A bookmark can open a web address, run a viewer action or point to a destination that no longer exists. Web links are shown with their address, and other entries are listed by title only.

### What if the PDF has no bookmarks?

The result says that the PDF has no bookmarks. Many documents have headings on their pages without an outline, because the outline must be created by the authoring program.

### How many bookmarks can be shown?

Up to 2,000 bookmarks nested up to 32 levels deep are listed. Longer outlines are cut at that point with a note, which still covers the contents of very long books.

### Is the outline returned as data too?

Yes. Besides the readable list, the result holds every entry with its nesting level, title, page and link, which is useful when the tool is called from scripts or AI assistants.

### Can I use the outline as a table of contents?

Yes. The list is written in Markdown, so you can copy it into documents, wikis or notes, and it keeps the indentation of chapters and sections.

### Can I read the outline of a protected PDF?

Yes. Enter the password and the tool opens the document with it. The password is used for this request only and never appears in the result.

### What are the file limits?

The PDF can be up to 10 MiB with at most 200 pages. The document is read in memory only and is not changed or stored.

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