How to Create a New Integral Symbol in LaTeX

A new integral sign in LaTeX is usually a custom command built from an existing symbol, rather than a newly designed font glyph. For example, you can put a star above the standard integral and define the result as an operator, so it accepts lower and upper bounds like an ordinary integral.

If you need a commonly used symbol, check whether a package already provides it. For a distinctive symbol that no font contains, you will need to draw or overlay a mark; \newcommand by itself only combines existing material.

Define a decorated integral

The following complete example creates \starint, an integral with a star above it. It uses the amsmath package for \overset.

\documentclass{article}
\usepackage{amsmath}

\newcommand{\starint}{\mathop{\overset{\star}{\int}}\nolimits}

\begin{document}
Inline: $\starint_{a}^{b} f(x)\,dx$.

Display:
\[
  \starint_{a}^{b} f(x)\,dx
  \qquad
  \starint\limits_{a}^{b} f(x)\,dx
\]
\end{document}

The command has two important parts. \overset{\star}{\int} places the star over the integral sign. The surrounding \mathop{...} tells LaTeX to treat the decorated result as a mathematical operator, so subscripts and superscripts attach as bounds rather than as ordinary text.

The final \nolimits makes the bounds sit beside the symbol by default, as they commonly do for integrals. In the display example, \limits explicitly moves them above and below. Remove \nolimits if you want the operator’s default limit placement instead. Test both inline and display math: a decoration can make the symbol taller and affect how crowded the bounds look.

Adapt the symbol

Replace \star with another small math symbol or a short expression that suits your notation. For example, \overset{\ast}{\int} uses an asterisk, while \underset{c}{\int} places a mark underneath. Keep the decoration compact; a wide or tall mark can make the integral difficult to read.

Give the command a name that explains its meaning, such as \myint while drafting or a notation-specific name in a document. Define it in the preamble, before \begin{document}. If you use the symbol repeatedly, a named command makes it easier to change the design consistently later.

For a special integral used in a field, first look for an established notation and a LaTeX package that supplies it. Packages such as esint provide additional integral symbols. Using a standard symbol is usually preferable to inventing a visually similar one, because readers may interpret a new decoration as having a special mathematical meaning.

When you need a genuinely new glyph

A macro can position existing symbols, but it cannot create a new glyph inside a math font. \DeclareMathSymbol assigns a command to a glyph that is already present in a symbol font; it does not draw the glyph. If you need a custom shape, you can build it with a drawing or overlay approach, or use a math font that already contains the character. Those methods require extra care with alignment, scaling, and different math styles.

For a one-off decoration, a composed command like the example is often sufficient. For a reusable publication symbol, check how it looks at different sizes and in subscripts before settling on the design. If it is meant to represent a mathematical operation, define and document its meaning as well as its appearance.

Common mistakes

• Defining only a visual expression: Without \mathop, a decorated integral may not behave like an operator when you attach bounds.
• Using \DeclareMathOperator for an integral: That command is intended for named operators such as \sin or \rank, not for shaping an integral sign.
• Assuming \newcommand creates a font character: It defines a macro, not a new glyph.
• Adding spacing commands too early: \mathop supplies operator spacing. Avoid inserting manual negative spaces unless you have checked the rendered result and have a specific reason.
• Inventing notation without checking conventions: A mark added to an integral may already have a recognized meaning in a particular subject.