How cross-reference fields in Word work

About cross-referencing in Word – what is a cross-reference? 

What is a cross-reference in Word?

In general, a cross-reference is a note in a text that tells you to look somewhere else in the text for more information.

In Word, you can insert dynamic cross-references that can be updated if the text you refer to changes.

Technically, a cross-reference in Word is a field, i.e. set of codes that instructs Word to automatically insert material into a document. The material inserted by cross-reference fields can be text, section numbers, paragraph numbers, caption numbers, caption labels, etc. The field code can also include special information (referred to as switches) that make the field act or look in a special way. For example, a cross-reference field may function as a hyperlink so you can jump directly to the target of the cross-reference by clicking the field.

As opposed to cross-references you type manually, the great advantage of using cross-reference fields is that you only need to update fields to have the cross-references corrected if you have made changes to the document.

How to insert a cross-reference in Word?

Note that you can only insert cross-references to content that already exits in the document. For example, you cannot insert a cross-reference to a heading that has not yet been added to the document. In case you want to refer to something in another document, you can create a hyperlink.
The purpose of the article is not to go into detail about how to insert cross-references in Word but to explain how cross-references work. For completeness, here are the steps to follow to insert a cross-reference using the built-in functionality of Word:

1. In your document, position the insertion point where the cross-reference is to be inserted.
2. In the Ribbon, select References tab > Captions group: Cross-references.
   Note that you will also find the command in Insert tab > Links group: Cross-references.
   
   The following takes place in the Cross-reference dialog box. See the illustration below.
3. In the Reference type list, select the type you want.
   
   You can select from: Numbered item, Heading, Bookmark, Footnote, Endnote plus caption types depending on which caption labels are available (e.g. Figure, Table, Equation). Note that the dialog box shows all types no matter whether there are any targets of the different types in your document.
4. In the Insert reference to list, select what type of content you want the cross-reference to show.
   
   The items in the list depend on what you selected as the reference type in step 3.
5. Turn on Insert as hyperlink if you want the cross-reference field to function as a hyperlink so users can click or Ctrl-click it to jump to the target.
6. In the For which list, select the item the cross-reference must refer to.
   The list is empty if no items match the reference type you selected.
7. Click Insert.

What to do if headings are missing in the Cross-reference dialog box?

In the illustration above, you can see that Heading is selected as the reference type in the Cross-reference dialog box. You can see that several headings are listed in the For which heading field.

If your document has a number of headings and if all or some of the headings are missing in the dialog box, you need to check the formatting of your document. All paragraphs that are formatted with one of the built-in styles Heading 1-9 are automatically shown in the dialog box. If you have used other styles for the headings, they will only appear in the heading list if the outline level of each of the headings has been set to one of the levels Level 1-9 in the Paragraph dialog box > Indents and Spacing tab > Outline level field. Headings with the outline level is set to Body Text will not appear in the target list.

Note that the style names of Heading 1, Heading 2, … , Heading 9 are language-specific. If your Word isn't English, you will see another word than "Heading" but still with the numbers 1-9. For example, the styles are named Overskrift 1, Overskrift 2, etc. in Danish.

See also Shauna Kelly's article Why use Microsoft Word’s built-in heading styles?

When inserting a cross-reference to a caption, a bookmark will also be used to enclose the part of the caption content that is to be displayed by the cross-reference field. The bookmark will enclose different parts of the caption depending on the kind of caption reference you select (e.g. the entire caption or only the label and number).

Example of cross-reference bookmark name

_Ref123456789

The underscore in start of the bookmark name results in the bookmark being handled as a hidden bookmark in Word. You cannot add hidden bookmarks manually, i.e. the built-in Bookmark dialog box doesn’t let you start a bookmark name with “_”.

Hidden bookmarks remain invisible on the screen even if you turn on display of bookmarks. In the Bookmarks dialog box, you must turn on Hidden bookmarks to have the hidden bookmarks listed in the dialog box.

Note that names of bookmarks added by DocTools CrossReferenceManager follow the same syntax rules as the bookmarks added by the built-in cross-reference functionality.

Note that cross-references do not update automatically. If cross-references refer to headings, bookmarks, numbers or other targets that have been changed, you need to update the fields to reflect the changes.

Understanding cross-referencing in Word and how cross-reference fields in Word work can save you from a lot of time and trouble with Word documents. I hope this article helps you in your future work with cross-references in Word.