Delta in LaTeX (\delta)

Where it is used

Lowercase Greek delta, used for small quantities, the Dirac delta function, and the Kronecker delta.

Analysis pairs it with epsilon in definitions of limits and continuity, as in |x - a| < \delta. The Dirac delta \delta(x) satisfies \int f(x)\delta(x - a)\,dx = f(a), and the Kronecker delta \delta_{ij} equals 1 when i = j and 0 otherwise. Calculus of variations writes \delta S for a variation, and chemistry uses \delta+ and \delta- for partial charges. It differs from \partial, which is the curly partial-derivative sign, and from the uppercase \Delta used for finite changes.

Minimal compilable example

Paste this into an empty .tex file and compile it with pdfLaTeX, XeLaTeX or LuaLaTeX.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
Delta: $\delta$

\[ \delta_{ij} = \begin{cases} 1 & i = j \\ 0 & i \neq j \end{cases} \]
\end{document}

Related symbols

• Delta (Upper)\Delta
• Gamma (Upper)\Gamma
• Epsilon\epsilon
• Gamma\gamma
• Epsilon (Variant)\varepsilon
• Beta\beta

Frequently asked questions

How do I write Delta in LaTeX?

Type \delta in math mode, for example $\delta_{ij} = \begin{cases} 1 & i = j \\ 0 & i \neq j \end{cases}$. It works in plain LaTeX without loading any package.

Which package do I need for \delta?

None. \delta is part of standard LaTeX, so it compiles with nothing in the preamble but the document class.

Can I use \delta in text mode, or only in math mode?

Only in math mode. Outside $...$ LaTeX stops with "Missing $ inserted", so write $\delta$ in running text. If you only need the glyph in text, paste the Unicode character δ instead (with XeLaTeX or LuaLaTeX and a font that has it).