Add Bookmarks to PDF

Bookmarks — the outline shown in a PDF reader's side panel — turn a long PDF into something people can navigate: click a chapter and the reader jumps to it. Scanned books, merged reports and exported slides usually have none. Type a simple list of titles and page numbers, indent the sub-sections, and this tool writes a proper PDF outline that works in Acrobat, Chrome, Edge, Preview and phone readers. It runs in your browser; the file is not uploaded.

How to use this tool

1. Choose the PDF. Press the button with the list empty to load any bookmarks it already has.
2. Write one bookmark per line as "Title | page". Indent a line (or start it with > or >>) to nest it under the line above.
3. If the printed page numbers differ from the PDF's, set the page offset.
4. Download the bookmarked PDF; the outline read back from the saved file is shown for checking.

Formula

Each line becomes an outline item with a Title (stored as UTF-16 so any language works), a destination [page /XYZ left top] and Parent/Prev/Next/First/Last links. Count tells readers how many items are visible: positive when a branch is expanded, negative when collapsed.

Page separators accepted: "|", a tab, dot leaders ("Title ..... 12") or a space before the final number — so a contents page copied from the PDF itself usually works as-is.

Example

A 120-page report whose printed page 1 is PDF page 5: enter Summary | 1, Findings | 6 and Appendix | 98 with an offset of 4. The outline points to PDF pages 5, 10 and 102, with Findings nested under Summary.