How to Automatically Generate a Book Index in Microsoft Word

Creating an index for a lengthy document, such as a thesis, manual, or book, is traditionally one of the most tedious tasks in publishing. Manually typing out keywords and constantly updating page numbers as the document changes is a recipe for errors. Fortunately, Microsoft Word includes a robust Indexing feature that allows you to tag keywords throughout your text and automatically generate a dynamic, alphabetized index at the end of your document.

Step 1: Mark Your Index Entries

Before Word can generate an index, you must explicitly tell it which words or phrases to include.

1. Read through your document and highlight the first word or phrase you want to appear in the index (e.g., “Photosynthesis”).
2. Navigate to the References tab on the Ribbon.
3. In the “Index” group, click the Mark Entry button. (Alternatively, press Alt + Shift + X on your keyboard).
4. The “Mark Index Entry” dialog box will appear.
   • Main entry: This will display the word you highlighted. You can change the capitalization here if desired.
   • Subentry: (Optional) If you want this word nested under a larger category, type the sub-category here.
5. Click the Mark button to tag this specific instance, or click Mark All to have Word automatically find and tag every occurrence of this word throughout the entire document.
6. The dialog box stays open, allowing you to click back into your document, highlight the next word, click back to the dialog, and hit Mark again.

Note: Marking entries turns on “Show/Hide Formatting Marks,” revealing hidden codes in your text like { XE "Photosynthesis" }. This is normal. You can turn this off later by clicking the paragraph symbol (¶) on the Home tab.

Step 2: Generate the Index

Once you have marked all relevant entries throughout your manuscript, you can compile the index.

1. Scroll to the very end of your document (or wherever you want the index to appear).
2. On the References tab, in the “Index” group, click Insert Index.
3. The Index configuration window will appear. Here you can customize the layout:
   • Formats: Choose a visual style (e.g., Classic, Fancy, Modern).
   • Columns: The default is 2 columns, which is standard for book publishing, but you can change it to 1 or 3.
   • Right align page numbers: Check this box to push the page numbers to the far right with a dotted leader, making it easier to read.
4. Click OK.

Step 3: Updating the Index

The generated index is dynamic. If you edit your document—adding paragraphs or deleting pages—the page numbers in your index will become inaccurate. Word does not update the index automatically as you type.

To refresh the index before final publication, simply click anywhere inside the generated index block to select it, right-click, and choose Update Field (or press F9). Word will instantly rescan the document and correct all the page numbers.