Word field codes provide a powerful way to customize how table of contents entries are displayed and structured. The standard TOC pulls in all headings based on their outline levels, you may wish to filter out specific heading tiers.

These scenarios are managed using the \t and \o switches, allowing fine-tuned inclusion of specific styles at designated depths.

The \o switch controls the depth of headings included in the TOC. The standard configuration is \o "1-3", which pulls in Heading 1, Heading 2, and Heading 3. You can adjust this range to match your document’s hierarchy. For example, if you are creating a technical manual and only want headings from level 1 to level 4 to appear in the table of contents, you would modify the switch to \o "1-4". Alternatively, if you prefer a streamlined TOC with only top-level sections, you can narrow the scope to \o "1-2".

To modify the field code, begin by right-clicking the TOC and selecting Edit Field. This will display the hidden field syntax, which commonly displays as TOC \o "1-3" \h \z . You can then manually change the number range after the \o switch. After making your changes, press F9 to update the field and see the updated table of contents.

Another useful switch is \t, which allows you to include custom styles in your table of contents. Out-of-the-box, Word ignores custom styles. But if you’ve created custom styles such as "Section Title" or "Appendix Heading", you can integrate them using \t. For instance, \t "Heading 1,1,Heading 2,2,Section Title,3" tells Word to map Heading 1 to level 1, Heading 2 to level 2, and Section Title to level 3. It allows logical organization of content outside typical heading norms.

It is important to note that when using the \t switch, the format must be exact. The style must be spelled identically to its appearance in the Styles pane, then a comma and the target level. Each pair is delimited by commas. Incorrect casing or spelling will prevent the style from being recognized.

Once field codes are edited, refresh the TOC via right-click > Update Field or by pressing F9. This makes certain your adjustments are visible. If you’ve inserted or deleted headings post-editing, regenerate the full TOC.

Customizing TOC levels via field switches is vital for lengthy documents like theses, reports, or legal briefs, where clarity and structure are critical. This enables you to adapt the TOC to reader expectations—whether they require a high-level overview or a detailed breakdown of subsections. Learning to use \t and \o effectively improves formatting precision and ketik document quality.