We’ve received a lot of feedback and questions about Word’s Table of Contents. Many questions come down to a core misunderstanding about Word – what Word calls ‘Headings’ aren’t really headings at all – they are outline levels.
‘Headings’ are different from ‘Outline Levels’ but sometimes Microsoft uses the term ‘Headings’ wrongly so confusion is understandable.
Have a look at this Table of Contents. It’s a genuine TOC made by Word … but look at the Navigation Pane on left.
Normally the Table of Contents and Navigation Pane are almost the same.
This one is blank! Why?
The document has headings, you can see them in the Table of Contents on right. So they should also appear in the Navigation Pane too?
No. A Table of Contents can be built without the essential part of the Navigation Pane – the Outline Level.
This problem is most likely to happen if you’ve created custom heading styles and by-passed the in-built ‘Heading n’ styles. When making the custom heading styles, setting the Outline Level is often (and understandably) overlooked.
According to Microsoft you can apply ‘Heading’ styles to fill in the Navigation Pane – but that’s not entirely true.
What are ‘Outline Levels’?
Outline Levels are Word’s way of organizing a document into the ‘tree’ structure that Microsoft calls an ‘interactive outline’. It’s better known as the Navigation Pane or Outline View.
The in-built Heading styles are linked to matching outline levels. ‘Heading 1’ style has outline level 1, ‘Heading 2’ style has outline level 2 and so on.
But the two can be separate properties.
- Outline Levels don’t have to be headings.
- Headings don’t necessarily have an outline level (but they usually will).
Mixed up terminology
Confusion arises because Microsoft uses the term ‘Headings’ when they should say ‘Outline Level’.
One example is the options available when saving to the PDF format. The dialog box talks about creating PDF bookmarks using ‘Headings’.
But that’s not true at all. The PDF bookmarks are created from Outline Levels – not Headings.
We’ve heard from readers who can’t understand why their document with a nice Table of Contents can’t create a PDF bookmark ‘tree’ (similar to Word’s Navigation Pane). In fact, the ‘Headings’ option is greyed out/disabled because there are no outline levels in the document.
Setting Outline Levels
Outline Levels are set in the Paragraph properties.
You can change the Outline Level for an individual paragraph but, more likely, you’ll change it in a style.
In Style settings choose Format | Paragraph and change the Outline Level.
As you can see in the style summary, the term ‘Level 1’ appears. If you look at any of the in-built Heading styles, you’ll see the outline level listed in the style summary. Here’s the default Heading 3 summary:
The default Outline Level is ‘Body Text’ – meaning that the paragraph does NOT appear in an outline view, Navigation Pane or Table of Contents based on outline levels. No ‘Level ‘ is shown in the style summary.
The Outline Level ‘Body Text’ has no direct link to the Style of the same name. The ‘Body Text’ style (like ‘Normal’ style) will usually be set to the ‘Body Text’ outline level – but that’s a coincidence of naming, nothing more. You could change the ‘Body Text’ style to have another Outline Level but you’d get a very messy Table of Contents and Navigation Pane!
It may have been better if the ‘Body Text’ outline level was called ‘None’ – but we’re stuck with it now.