\settoheight

\settoheight{len-cmd}{text}

The \settoheight command sets the value of a length command, len-cmd, which is specified as the first argument, equal to the maximum height of the text argument in the current font.

For example,

  \settoheight{\baselineskip}{Xanadu}
  \setlength{\baselineskip}{1.5\baselineskip}