Reducing font size in equation

Question

I wanted to type an equation in LaTeX. But it is too long to fit into one line. It involves big arrays with many columns so I cannot split it. I wanted to reduce the font size so that it can fit in one line. However, \small doesn't work in the equation environment.

Answer 1

Similar to How to make math font huge, you can use \scalebox to scale down the equation, or \resizebox the box to a specific width to reduce the size. The first is the normal display mode equation, followed by the scaled version with \scalebox and \resizebox:

Code:

\documentclass{article}
\usepackage{amsmath}
\usepackage{graphicx}
\newcommand*{\Scale}[2][4]{\scalebox{#1}{$#2$}}%
\newcommand*{\Resize}[2]{\resizebox{#1}{!}{$#2$}}%
\begin{document}
\[y = \sin^2 x\]
%
\[\Scale[0.5]{y = \sin^2 x}\]
%
\[ \Resize{1cm}{y = \sin^2 x}\]
\end{document}

Answer 2

Just put \small before the equation and \normalsize after it if you want to shrink the font, but it's usually better to use an ams multi-line equation environment than to change font size.

It's actually easier to only do the part of a size change command that affects math without changing the baseline to avoid the problems @barabara-beeton mentions. This is a \tiny (5pt) equation in a \large paragraph text, to highlight the differences, and to show that the above and below display skips are not altered.

\documentclass{article}

\showoutput
\showboxdepth3

\begin{document}
\large

hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
$$abc+xyz=44$$
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 

hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
\begingroup\makeatletter\def\f@size{5}\check@mathfonts
$$abc+xyz=44$$\endgroup
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 


\end{document}

---

with AMS align this would produce:

\documentclass{article}
\usepackage{amsmath}

\showoutput
\showboxdepth3

\begin{document}
\large

hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
\begin{align}
abc&+xyz&&=44\\
x&-y&&=2\\
a&+b&&=77
\end{align}
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 

hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
hghghga hghghga hghghga hghghga hghghga hghghga hghghga 
\begingroup\makeatletter\def\f@size{5}\check@mathfonts
\def\maketag@@@#1{\hbox{\m@th\large\normalfont#1}}%
\begin{align}
abc&+xyz&&=44\\
x&-y&&=2\\
a&+b&&=77
\end{align}\endgroup
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 
bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb bbbbbb 


\end{document}

Answer 3

The following illustrates font size alterations in mathmode:

\documentclass[letterpaper]{article}
\usepackage{graphicx}               % Necessary to use \scalebox
\usepackage{amsmath,amssymb}
\begin{document}
\noindent 
normal: $ x^2 + 2xy + y^2 $\\
displaystyle: $ {\displaystyle x^2 + 2xy + y^2} $\\
scriptstyle: $ {\scriptstyle x^2 + 2xy + y^2} $\\
scriptscriptstyle: $ {\scriptscriptstyle x^2 + 2xy + y^2} $\\
textstyle: $ {\textstyle x^2 + 2xy + y^2} $

\noindent
\scalebox{0.5}{%
normal: $ x^2 + 2xy + y^2$}
\end{document}

This yields:

Note that:

• \displaystyle gives the command to switch the math font size to normal size for displayed formulas.
• \textstyle is used to go back to normal size font for inline formulas.
• \scriptstyle is used to set the math font to a size used for subscripted and superscripted symbols.
• scriptscriptstyle provides the normal size for doubly subscripted and superscripted symbols.

When using the \scalebox command from the graphicx package one can specify the width (or height) and the other dimension will be scaled proportionally. In a similar manner you can specify both dimensions, but in this case it is all about aesthetics. Therefore we have the following under the \scalebox command:

• \scalebox{h-dimension}{v-dimension}{content to be scaled}: both dimension stated.
• \scalebox{h-dimension}{content}: both arguments (h-dim and v-dim) scaled with respect to the stated dimension.