Add bookmarks to a PDF

Type your outline entries below (one per line). Indent with a tab or spaces for child entries. Add page numbers with two spaces + p then the number (e.g. " p5"). Your file never leaves your device.

How Add PDF bookmarks works

PDF Bookmarks lets you add a clickable outline, a table of contents, to any PDF, mapping chapter titles or section headings to their page numbers and supporting nested levels. Readers can then jump directly to any section from the sidebar of any PDF viewer, making long documents much easier to navigate.

The tool works on PDFs that have no existing outline or whose outline was lost during conversion. It does not alter the page content itself, only the document's navigation structure, built with pdf-lib. You can set an indentation level per entry to nest chapters and sub-sections, and the outline follows the standard PDF spec so it shows in Acrobat, Preview and browser PDF viewers.

Frequently asked questions

Can I add nested bookmarks (chapters with sub-sections)?

Yes. You can set the indentation level for each entry, creating a hierarchy of chapters, sections and sub-sections, just as you would see in a well-structured PDF exported from a word processor.

Will this overwrite existing bookmarks in the PDF?

Adding new bookmarks replaces the existing outline. If you want to keep existing entries, export the current outline first, merge it with your new entries, then apply the combined set.

Do the bookmarks work in all PDF viewers?

Bookmarks follow the standard PDF outline specification and display in Adobe Acrobat Reader, Preview (macOS), browsers with built-in PDF viewers (Chrome, Firefox, Edge) and most other compliant readers.

Are my files uploaded to a server?

No. Your PDF is parsed and rewritten by pdf-lib in your browser tab, the document is loaded into memory on your own device, the outline (bookmark) dictionary is built and attached there, and the new PDF is serialised in memory and offered as a local download. Nothing reaches Sunasty or any third party. Open your browser's DevTools, go to the Network tab and watch: no request carries your file.

Does it work offline?

Yes, once the page has loaded. Because the processing happens on your device, you can disconnect from the network and the tool keeps working. This is the clearest proof that your data never leaves your machine.

Is it free? Do I need an account?

It is completely free and requires no sign-up. There are no watermarks, no daily limits and no tracking cookies needed to use the tool.

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