Epsilon (Variant) in LaTeX (\varepsilon)

Where it is used

Lowercase variant epsilon ε, the open curly form often preferred for error terms and small numbers.

\varepsilon renders the rounded ε shape, which looks closer to handwritten epsilon than the lunate \epsilon. Statistics writes the noise term of a regression as \varepsilon_i \sim \mathcal{N}(0, \sigma^2), and many analysis textbooks prefer \varepsilon in epsilon-delta proofs. Physics uses \varepsilon_0 for vacuum permittivity and \varepsilon_{ijk} for the Levi-Civita symbol. Since the two forms are easily mixed by accident, consider redefining one in your preamble so you only type a single command. Avoid using it as a stand-in for set membership \in.

Minimal compilable example

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

\documentclass{article}
\begin{document}
Epsilon (Variant): $\varepsilon$

\[ y_i = \beta_0 + \beta_1 x_i + \varepsilon_i \]
\end{document}

Related symbols

• Zeta\zeta
• Epsilon\epsilon
• Eta\eta
• Delta (Upper)\Delta
• Theta\theta
• Delta\delta

Frequently asked questions

How do I write Epsilon (Variant) in LaTeX?

Type \varepsilon in math mode, for example $y_i = \beta_0 + \beta_1 x_i + \varepsilon_i$. It works in plain LaTeX without loading any package.

Which package do I need for \varepsilon?

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

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

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