How to write percent(%) symbol in LaTeX?

If you use backslash \ before the percent % symbol in latex, you will return % symbol as the output.

And this is the easiest way to represent % symbol in a document.

Symbol	Percent
Type of symbol	Operator
Package	No
Argument	No
Latex command	\%
Example	A \% B → A % B

\documentclass{article}
\begin{document}
   \[ \frac{2}{5} = 40\% \]
   \[ \frac{3}{5} = 60\% \]
\end{document}

Output :

By mistake, you will always try to use the keyboard’s percent symbol indirect text. However, as a result, you will not see any percentage symbol as output.

\documentclass{article}
\begin{document}
% latex percent symbol
  $ 0.6 = 60\% $
\end{document}

Output :

Because % symbol in latex is only used to represent single line comment.

Insert percentage symbol in text

In the case of text mode, you need to add \ symbol before % symbol. There is no separate rule for this.

If you use only a percentage(%) symbol in a text, the text on the right side of the percentage symbol will be converted to a single-line comment.

\documentclass{article}
\begin{document}
   50\% means 50 per 100 \\[4pt]
   25% means 25 per 100
\end{document}

Output :

Use siunitx package for value and percentage symbol

In this package, the percent symbol has been considered as SI Unit. As a result, you can print the value and symbol together in the document.

\documentclass{article}
\usepackage{siunitx}
\begin{document}
    \[ \qty{75}{\percent} = \frac{75}{100}  \]  
    \[ \qty[color=red]{45}{\percent} = \frac{45}{100}  \] 
    \[ \qty[unit-color=red]{32}{\percent} = \frac{32}{100}  \] 
\end{document}

Output :