Math symbol reference

Double-Struck Italic e

Can represent Euler's number in typographic systems that distinguish constants from variables.

UnicodeU+2147
LaTeX\mathbb{e}
HTML entity
HTML decimalⅇ
MathML<mi>ⅇ</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 ConstantsMathematical Alphanumeric Symbols

MathML token

<mi>

Treat ⅇ 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

  • ⅈ — Double-Struck Italic i
  • π — Pi

Use ⅇ in the right format

Meaning and usage

Can represent Euler's number in typographic systems that distinguish constants from variables.

Use it consistently with the mathematical style of the surrounding document.

Pronunciation: double-struck italic e

Formula examples

e^{i\pi}+1=0

How to type Double-Struck Italic e

Windows
Use Character Map and search for Double-Struck Italic e, or paste the Unicode character (U+2147).
macOS
Open Character Viewer with Control–Command–Space and search for Double-Struck Italic e.
Microsoft Word
In an equation, type \mathbb{e} and press Space when Word supports the command; otherwise insert the Unicode character.
iPhone and iPad
Copy and paste ⅇ, or use a math/LaTeX app. The standard iOS keyboard may not expose every mathematical symbol.
Android
Copy and paste ⅇ, or use a math keyboard or LaTeX editor. Keyboard layouts vary by device and app.
Google Docs
For plain text, paste ⅇ or use Insert → Special characters. For structured math, use the equation editor and verify \mathbb{e}.
Excel
Paste ⅇ into a cell or use Insert → Symbol when available. Ordinary cells preserve the character but do not interpret LaTeX commands.

Common mistakes

  • Do not substitute a visually similar Latin or differently styled character for ⅇ; case and mathematical alphabet style can identify different quantities.
  • For plain text, copy ⅇ as U+2147; for structured equations, use \mathbb{e} in math mode. A look-alike glyph or image can break search, accessibility, or parsing when the intended character is Double-Struck Italic e.

When to use ⅇ

  • Use ⅇ in plain text when a Unicode character is appropriate and the destination preserves U+2147.
  • Use \mathbb{e} in an equation editor when mathematical spacing or structure matters.
  • Define the local meaning when Double-Struck Italic e is used in constants, math alphanumeric with a field-specific convention.

Look-alikes and related characters

  • ⅈ — Double-Struck Italic i
  • π — Pi

Font and compatibility notes

Font coverage varies; verify the code point and destination rendering before publication.

Continue the workflow

From Double-Struck Italic e to a finished equation

  1. Copy the characterUse ⅇ in plain text when Unicode is accepted.
  2. Choose a structured formatUse \mathbb{e} 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: catalog

Last reviewed: 2026-07-23

Review method: Catalog review of character identity and notation mappings.

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

Reference sources

Frequently asked questions

What does the Double-Struck Italic e symbol mean?

Can represent Euler's number in typographic systems that distinguish constants from variables.

What is the LaTeX command for ⅇ?

Use \mathbb{e} in a compatible math environment.

Can I copy ⅇ as Unicode?

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

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