Hi
one complication is that the last line width is not available outside math mode (which is a pain)
If really needed one can use quite old plain macro which try to soften this pain... However for short paragraphs it needs some changes (\prevgraf can't be less then zero). Meybe this is not very nice but... \newif\ifmeasdisp \measdispfalse \newcount\lineno \newdimen\linesize \def\measline{\ifhmode \bgroup \parfillskip=0pt plus 1fil \predisplaypenalty=10000 \postdisplaypenalty=10000 \displaywidowpenalty=\widowpenalty \abovedisplayskip=-\baselineskip \belowdisplayskip=-\baselineskip \abovedisplayshortskip=-\baselineskip \belowdisplayshortskip=-\baselineskip $$\global\linesize=\predisplaysize$$ \global\advance\linesize by -2em \global\lineno=\prevgraf \global\advance\lineno by -3 \ifmeasdisp\immediate\write16{>>\the\lineno: \the\linesize}\fi \global\advance\lineno by -1 \global\prevgraf=\lineno \kern\linesize \egroup \else \immediate\write16{! I'M IN VMODE---MEASURING IGNORED}% \fi} % ------------------------------------------------------------------------ % Author: B. Jackowski, 22 V 1990. % ------------------------------------------------------------------------ Regards