Add Bookmarks to PDF

How to use

1. Choose a PDF. Any bookmarks it already has are loaded into the text box.
2. Write one bookmark per line with the page number at the end, indenting lines to nest them — or click "Generate from headings".
3. If printed page numbers differ from PDF pages, fill in "Printed page 1 is PDF page".
4. Click bookmarks in the preview to check the pages, then download the PDF with bookmarks.

Options explained

Indentation

Leading spaces, tabs or full-width spaces set the level. A line indented deeper than the one above is nested under it; equal indentation means the same level. Any number of spaces works.

Page offset

Scanned books start with a cover, copyright page and preface, so printed page 1 is often PDF page 10 or later. Enter that PDF page and you can type the page numbers printed in the book.

=page

Write "=3" to point straight at PDF page 3 without the offset — for the preface or contents pages that come before page 1.

Use numbering for levels

Contents copied from a book usually lose their indentation. Tick this to nest by numbering instead — Part, Chapter, then 1.1 and 1.1.1.

Bookmark panel

Open with every level expanded, or with only the top level showing, which suits long books.

How to write the contents

One bookmark per line: the title, then the page number, separated by spaces, a tab or a row of dots. Indent a line to nest it:

Preface =5
Chapter 1 Introduction 1
  1.1 Background 3
  1.2 Methods 8
    1.2.1 Survey design 9
Chapter 2 Results 15
References .......... 86

With “Printed page 1 is PDF page” set to 13, this produces:

A line without a page number, such as a part title, takes the page of the next bookmark that has one. Lines pointing past the last page are listed above the preview, and the download stays disabled until they are fixed.

Finding the page offset

Go to the page with “1” printed on it and note which PDF page your reader shows; enter that number. If the cover, copyright page, preface and contents take 12 pages, printed page 1 is PDF page 13. Front-matter pages numbered i, ii, iii are best given as “=PDF page”.

Some books have unnumbered colour plates in the middle, which shifts everything after them. Write the bookmarks after the plates as “=PDF page”, or do the book in two passes with different offsets.

Copying a book’s contents page

1. If the PDF has a text layer, open it in PDF to Text and copy the contents pages.
2. Paste into the text box and delete stray lines such as running headers.
3. Copied contents rarely keep their indentation, so tick “Use numbering for levels”. Numbered lines (Chapter 1, 1.1) are nested automatically; unnumbered ones such as Preface, References and Appendix go to the top level.
4. Set the page offset and click a few bookmarks in the preview to make sure they land on the right pages.

Generating bookmarks from headings

PDFs exported from Word without “Create bookmarks” ticked have no bookmarks, but their headings are set larger than the body text. “Generate from headings” reads each page’s text, treats lines at least 15% larger than the body and reasonably short as headings, and ranks the three largest sizes as three levels. A heading that wraps onto two lines is joined back together.

The result replaces the text box (Undo brings the old text back). Expect to delete a few false hits, such as large figure captions or the title page. Next time, in Word’s Save as PDF options tick “Create bookmarks using: Headings” and the PDF will have bookmarks from the start.

Merged bundles

Applications, expense claims and multi-part reports are often several PDFs merged together. In Merge PDF, tick “Add a bookmark for each file” to get one bookmark per file, with each file’s original bookmarks nested beneath it. To rename or rearrange them afterwards, open the merged file here.

Frequently asked questions

Privacy

This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.