textwidth

Textwidth is a typographic term that describes the horizontal extent of the main body of text on a page or in a column. It represents the width available for lines of ordinary text, excluding margins, headers, footnotes, and other marginal material. The measure is important for determining line length and page balance.

In TeX and LaTeX, textwidth is a specific length that defines the width of the text area on the page. It is determined by the page geometry and can be queried or set through the document class, margins, and column layout. In TeX, related dimensions include \hsize, while LaTeX uses \textwidth as the public name for the text area width. In single-column documents, textwidth corresponds to the line length used by wrapping; in multi-column layouts, it typically equals the width of a single column.

Adjusting textwidth is commonly done via page layout tools such as the geometry package in LaTeX, or by directly redefining \textwidth. Changes to textwidth affect both line length and the overall appearance of the page, including where margins and whitespace appear. A larger textwidth produces longer lines and can influence readability and page balance, while a smaller textwidth results in shorter lines. The widely cited readability guideline suggests aiming for roughly 50 to 75 characters per line, though optimal values depend on font, spacing, and audience.

Outside of TeX, the concept appears in other typesetting and web contexts as the width of a text block or content area, though the exact terminology and implementation differ.