LaTeX Sigma (σ) - Complete Guide

The Greek letter sigma (σ/Σ) is used for standard deviation, conductivity, and summation.

Symbol Preview

σ

Sigma

LaTeX Code

No package required

Recommended
\sigma

Lowercase sigma

No package required

Recommended
\Sigma

Uppercase sigma (summation)

Requires: \usepackage{cmd.package}

\varsigma

Alternative lowercase sigma (final sigma)

What is the LaTeX Sigma?

Sigma is the eighteenth letter of the Greek alphabet. Lowercase σ represents standard deviation in statistics and conductivity in physics. Uppercase Σ is the summation symbol used to denote the sum of a series. Both forms are fundamental in mathematics and science.

How to Use Sigma in LaTeX

Method 1: Using \sigma

✅No package required

Lowercase sigma

Example: Using \sigma

latex
\documentclass{article}

\begin{document}

% Using the Sigma
Text with \sigma

\end{document}

Method 2: Using \Sigma

✅No package required

Uppercase sigma (summation)

Example: Using \Sigma

latex
\documentclass{article}

\begin{document}

% Using the Sigma
Text with \Sigma

\end{document}

Method 3: Using \varsigma

⚠️Required Package:

\usepackage{cmd.package}

Alternative lowercase sigma (final sigma)

Example: Using \varsigma

latex
\documentclass{article}
\usepackage{amssymb}
\begin{document}

% Using the Sigma
Text with \varsigma

\end{document}

Common Use Cases

The Sigma symbol is commonly used in the following contexts:

Standard Deviation

Represents standard deviation in statistics.

Code

Standard deviation: $\sigma = \sqrt{\frac{1}{N}\sum_{i=1}^{N}(x_i-\mu)^2}$

Output

Standard deviation: σ = √((1/N)Σ(x_i-μ)²)

Summation

Uppercase sigma for summing series.

Code

Sum: $\Sigma_{i=1}^{n} i = \frac{n(n+1)}{2}$

Output

Sum: Σ(i=1 to n) i = n(n+1)/2

Electrical Conductivity

Used in physics for conductivity.

Code

Conductivity: $\sigma = \frac{1}{\rho}$

Output

Conductivity: σ = 1/ρ

Complete Examples

Summation Formula

Summation formula using uppercase sigma

latex
\documentclass{article}
\begin{document}

The sum of the first $n$ natural numbers: $\Sigma_{i=1}^{n} i = \frac{n(n+1)}{2}$

\end{document}

Normal Distribution

Standard deviation using sigma

latex
\documentclass{article}
\begin{document}

In a normal distribution, about 95% of values fall within 2 standard deviations: $\mu \pm 2\sigma$

\end{document}

Frequently Asked Questions

Which method should I use?

We recommend using the method marked as "Recommended" above. However, the best method depends on your specific needs:

  • \sigma: Lowercase sigma
  • \Sigma: Uppercase sigma (summation)
  • \varsigma: Alternative lowercase sigma (final sigma)

Where do I use this symbol?

This symbol can be used:

  • In mathematical equations (math mode)
  • In regular text (if using text mode)
  • In various document environments

Can I use this in display mode?

Yes, symbols that work in math mode (between $ $) also work in display mode (between $$ $$). This allows you to display the symbol on its own line with larger formatting.

🔗 Related Symbols You May Need

ρ

Rho

\rho
τ

Tau

\tau
View all symbols →

🎯 Need to Convert PDF to LaTeX?

Our free PDF to LaTeX converter preserves all mathematical symbols and formatting.

✓ Fast & accurate

✓ Preserves symbols

✓ Free online

✓ No registration

Try Converter Now →