LaTeX Lengths

A length is a measure of distance. Many LaTeX commands take a length as an argument.

\newlength

\newlength{\gnat}
The \newlength command defines the mandatory argument, \gnat, as a length command with a value of 0in. An error occurs if a \gnat command already exists.

\setlength

\setlength{\gnat}{length}
The \setlength command is used to set the value of a length command. The length argument can be expressed in any terms of length LaTeX understands, i.e., inches (in), millimeters (mm), points (pt), etc.