How to Create a Single-Item List with enumitem

If you need the same one-item numbered list in several places, define a custom list environment with the enumitem package. This keeps the formatting consistent and avoids repeating list options each time.

The example below defines an enumerate-based environment called singleitem. Use one \item inside it whenever you want a single numbered entry.

Define the environment

\documentclass{article}
\usepackage{enumitem}

\newlist{singleitem}{enumerate}{1}
\setlist[singleitem]{label=\arabic*., leftmargin=*}

\begin{document}

\begin{singleitem}
  \item This is the one item in the list.
\end{singleitem}

\end{document}

This is a complete document. \newlist{singleitem}{enumerate}{1} creates a new list type named singleitem, using enumerate as its base and allowing one nesting level. \setlist[singleitem]{...} sets options for that list type. Here, label=\arabic*. gives the item an Arabic numeral followed by a period, and leftmargin=* lets enumitem calculate a suitable left margin from the label.

The displayed item is numbered 1.. Since each use of this custom list begins a new list, its numbering starts at 1 each time.

Add one item each time

The environment does not impose a one-item limit. It is still an enumerate-style list, so LaTeX will accept multiple \item commands:

\begin{singleitem}
  \item First entry.
  \item Second entry.
\end{singleitem}

That produces a two-item list. In ordinary use, the name singleitem serves as a reminder to put only one \item in the environment; defining a custom list this way does not make LaTeX check or enforce that convention. If you need a hard restriction, you would need a more specialized macro or environment.

Change the label or spacing

You can choose a different label by changing the label option. For example, use a parenthesized number with label=(\arabic*), or lowercase letters with label=\alph*.. The starred counter form is supplied by enumitem and is replaced by the current item’s counter value.

You can also adjust list spacing. For example:

\setlist[singleitem]{
  label=\arabic*.,
  leftmargin=*,
  nosep
}

nosep removes the usual extra vertical space around and between list items. Because this list has only one item, the most noticeable effect is often the reduced space above and below the list. Remove nosep if you want the document class’s regular list spacing.

To change the format at just one use, pass options to the environment instead of changing the preamble setting:

\begin{singleitem}[label=\textbullet, leftmargin=*]
  \item A single bullet-style entry.
\end{singleitem}

Local options override the corresponding settings for that list instance. This example changes the label but still uses the custom environment’s other settings.

Common mistakes

• Forgetting enumitem: The \newlist and \setlist commands come from enumitem, so include \usepackage{enumitem} in the preamble.
• Using \item outside the environment: Each entry must be inside \begin{singleitem} and \end{singleitem}.
• Expecting the list to enforce one item: The environment supports multiple items; it does not validate how many you include.
• Assuming existing enumerate settings automatically carry over: A custom list type can have its own settings. Specify the label and any spacing options you want for singleitem with \setlist.

If you only need a one-item list once, an ordinary enumerate with a single \item is sufficient. Define a custom environment when you want a reusable name or consistent formatting across the document.