This is a list of symbols found within all branches of mathematics to express a formula or to represent a constant.

When reading the list, it is important to recognize that a mathematical concept is independent of the symbol chosen to represent it. For many of the symbols below, the symbol is usually synonymous with the corresponding concept (ultimately an arbitrary choice made as a result of the cumulative history of mathematics), but in some situations a different convention may be used. For example, depending on context, the triple bar "≡" may represent congruence or a definition. Further, in mathematical logic, numerical equality is sometimes represented by "≡" instead of "=", with the latter representing equality of well-formed formulas. In short, convention dictates the meaning.

Each symbol is shown both in HTML, whose display depends on the browser's access to an appropriate font installed on the particular device, and typeset as an image using TeX.

This list is organized by symbol type and is intended to facilitate finding an unfamiliar symbol by its visual appearance. For a related list organized by mathematical topic, see List of mathematical symbols by subject. That list also includes LaTeX and HTML markup and Unicode code points for each symbol.

**Basic symbols:** Symbols widely used in mathematics, roughly through first-year calculus. More advanced meanings are included with some symbols listed here.
**Symbols based on equality "=":** Symbols derived from or similar to the equal sign, including double-headed arrows. Not surprisingly these symbols are often associated with an equivalence relation.
**Symbols that point left or right:** Symbols, such as < and >, that appear to point to one side or another.
**Brackets:** Symbols that are placed on either side of a variable or expression, such as | *x* |.
**Other non-letter symbols:** Symbols that do not fall in any of the other categories.
**Letter-based symbols:** Many mathematical symbols are based on, or closely resemble, a letter in some alphabet. This section includes such symbols, including symbols that resemble upside-down letters. Many letters have conventional meanings in various branches of mathematics and physics. These are not listed here. The See also section, below, has several lists of such usages.
**Letter modifiers:** Symbols that can be placed on or next to any letter to modify the letter's meaning.
**Symbols based on Latin letters**, including those symbols that resemble or contain an X
**Symbols based on Hebrew or Greek letters** e.g. ב ,א, δ, Δ, π, Π, σ, Σ, Φ. *Note:* symbols resembling Λ are grouped with "V" under Latin letters.
**Variations:** Usage in languages written right-to-left
*Includes upside-down letters.*

Also called diacritics.

In mathematics written in Arabic, some symbols may be reversed to make right-to-left writing and reading easier.