# Change font size of one equation in align environment

\begin{align}
\label{e1}
a+b&=c\\
\label{e2}
a+b+c+d+e+f+g+h+i+j+k+l&=1+2+3+4+5+6+7+8+9\\
\label{e3}
c+d&=e
\end{align}


From this page I am able to reduce the font size of all equations. But, how to change the font size of only one equation (e2).

• you could use \scriptstyle but any change of the font size there is going to look horrible can you not split the line? Also please always post complete documents that show the problem, not just fragments (in particular you have given no indication of the required line width here) Oct 8, 2017 at 12:00
• Changing size of one equation in a multiline display should be the very last resort. Maybe, if you show the real problem you're facing, some better suggestion can come up. Oct 8, 2017 at 12:02

Another possibility would be the \medmath command from nccmath, which sets the math fontsize between \scriptstyle and \displaystyle (~ 80 % of \displaystyle):

\documentclass{article}
\usepackage{mathtools, nccmath}

\begin{document}

\begin{align}
\label{e1}
a+b & = c \\
\label{e2}
\medmath{a+b+c+d+e+f+ g+h+i+j+k+l} & = \medmath{ 1+2+3+4+ 5+6+7+8+9}\\
\label{e3}
c+d & = e
\end{align}

\end{document}


A last possibility in some cases, if you don't use margin notes, consists in loading the geometry package, which produces more decent margins and thus slightly increases text width.

\documentclass{article}
\usepackage{mathtools}

\begin{document}
\begin{align}
\label{e1}
a+b & = c                   \\
\label{e2}
\begin{multlined}[b]a+b+c+d+e+f+\\
g+h+i+j+k+l
\end{multlined} & = \begin{multlined}[t]1+2+3+4+\\
5+6+7+8+9
\end{multlined}     \\
\label{e3}
c+d & = e
\end{align}
or
\begin{align}
\label{e1}
a+b & = c                   \\
\label{e2}
A   & = B    \\
\label{e3}
c+d & = e
\end{align}
where are
\begin{align}
A & = a+b+c+d+e+f+g+h+i+j+k+l   \label{eq:A}    \\
B & = 1+2+3+4+5+6+7+8+9         \label{eq:B}
\end{align}

\end{document}

• This trick will not work in my case, I tried breaking into multiline, your tricks etc. Thanks. Oct 8, 2017 at 12:25
• @Mr.EU, it works, but you not liked it :-). from my experiences, the most readers will lost in your long equations (one of my colleagues make research how many items people observe in one line: experienced 9, less experienced 7 and not experienced 5, it is good to keep this in mind when you write equations too ;-) ). changing font size middle of equation is to my taste aesthetical unpleasant. Oct 8, 2017 at 12:51