Math symbol reference

Infinity

Represents an unbounded quantity or limit concept rather than an ordinary real number.

UnicodeU+221E
LaTeX\infty
HTML entity∞
HTML decimal∞
MathML<mi>∞</mi>

Semantic identity and intent

Semantic type

constant

A named mathematical constant or fixed symbolic quantity.

Primary search task

identify the constant, understand its role, and copy the correct notation

Mathematical ConstantsCalculus Symbols

MathML token

<mi>

Treat ∞ as a named mathematical constant only when the surrounding field defines that convention. The same glyph can be an ordinary variable in another context, so preserve the local definition.

Characters to distinguish

  • ℝ — Real Numbers

Use ∞ in the right format

Meaning and usage

Represents an unbounded quantity or limit concept rather than an ordinary real number.

Use it in limits, intervals, cardinality, and descriptions of unbounded behavior.

Pronunciation: infinity

Formula examples

\lim_{x\to\infty}1/x=0
(-\infty,0)

How to type Infinity

Windows
Use Character Map or enter U+221E in a Unicode-aware app.
macOS
Open Character Viewer with Control–Command–Space and search by name.
Microsoft Word
Type \infty in an equation and press Space.
iPhone and iPad
Copy and paste ∞, or use a math/LaTeX app. The standard iOS keyboard may not expose every mathematical symbol.
Android
Copy and paste ∞, or use a math keyboard or LaTeX editor. Keyboard layouts vary by device and app.
Google Docs
For plain text, paste ∞ or use Insert → Special characters. For structured math, use the equation editor and verify \infty.
Excel
Paste ∞ into a cell or use Insert → Symbol when available. Ordinary cells preserve the character but do not interpret LaTeX commands.

Common mistakes

  • Check whether ∞ is acting as an operator, differential, index, or variable in the surrounding expression; Use it in limits, intervals, cardinality, and descriptions of unbounded behavior.
  • For plain text, copy ∞ as U+221E; for structured equations, use \infty in math mode. A look-alike glyph or image can break search, accessibility, or parsing when the intended character is Infinity.

When to use ∞

  • Use ∞ in plain text when a Unicode character is appropriate and the destination preserves U+221E.
  • Use \infty in an equation editor when mathematical spacing or structure matters.
  • Define the local meaning when Infinity is used in constants, calculus with a field-specific convention.

Look-alikes and related characters

  • ℝ — Real Numbers

Font and compatibility notes

Glyph shape can vary by font. Verify the code point after copying, and prefer LaTeX or MathML for structured equations.

Continue the workflow

From Infinity to a finished equation

  1. Copy the characterUse ∞ in plain text when Unicode is accepted.
  2. Choose a structured formatUse \infty for LaTeX or the MathML snippet for accessible web equations.
  3. Edit or convertOpen the value in the editor or converter without retyping it.

Review and source notes

Quality tier: core

Last reviewed: 2026-07-26

Review method: Checked Infinity against its Unicode identity, LaTeX representation, HTML serialization, MathML token, and copy-and-paste behavior.

Verified against: Unicode Standard, Unicode mathematical notation guidance, and established LaTeX/MathML syntax.

Reference sources

Frequently asked questions

What does the Infinity symbol mean?

Represents an unbounded quantity or limit concept rather than an ordinary real number.

What is the LaTeX command for ∞?

Use \infty in a compatible math environment.

Can I copy ∞ as Unicode?

Yes. Use the copy button above to copy the Unicode character directly.

Reuse, attribution, and correction

Share this reference without losing its source

Copy a citation, permanent link, Markdown link, or self-contained embed card. Each reusable format points readers back to the maintained canonical page.

Report an issue

Search the whole reference

Symbols, formulas, guides, tools and commands

Start typing to search.

move · Enter open · Esc close