About Asterisk Operator
Asterisk Operator is the Unicode character ∗ at codepoint U+2217 in the Mathematical Operators block of the Basic Multilingual Plane (BMP).
Reference
The asterisk, centred as an operator. General category Sm, in Mathematical Operators since Unicode 1.1, East Asian Width Narrow, and with no Windows-1252 slot — the difference from the keyboard asterisk in one line. It sits on the same vertical axis as a plus or a minus rather than up where a footnote reference belongs. Unicode's code chart carries one annotation for it, and it is not about mathematics: the character "may be used to represent the telephony asterisk seen on keypads". HTML names it ∗. Unicode's confusables data (UTS #39) folds it directly into U+002A, so the standard formally records that the two are indistinguishable to a reader.
Typical uses
- A generic binary operation in typeset mathematics, where the point is that some operation applies
- Convolution, complex conjugation, and other conventions that borrow the star
- The keypad asterisk, per the code chart's own annotation
At a glance
- U+2217, Mathematical Operators; Unicode 1.1; general category Sm
- East Asian Width Narrow; line break class AL
- HTML: ∗. No Windows-1252 slot
- Confusable with U+002A by UTS #39; Unicode's mathematical classification calls it binary
Historical Notes
Origins
Unicode 1.1, 1993, in the original Mathematical Operators block. Its reason for existing is vertical position: the ASCII asterisk sits high, where a reference mark belongs, and an operator between two operands has to sit on the operands' axis. Same star, different altitude.
The one annotation is about telephones
The code chart's single note says the character may be used for the telephony asterisk seen on keypads. That is the standard's only stated use for it, and it has nothing to do with the block it lives in — a good reminder that Unicode's annotations record what a character was needed for, not what it ought to mean.
Why it stayed unused
It has no Windows-1252 byte and a keyboard key that draws something almost identical. Not being typable on a Western keyboard for a generation is the likeliest reason it never became a character people write.
Developer Notes
| Unicode Codepoint | |
| Decimal | |
| UTF-8 (hex) | |
| UTF-16 (hex) | |
| HEX Entity | |
| HTML Entity | |
| CSS (\xxxx) | |
| JavaScript | |
| Python |
How to Use Asterisk Operator
To use the Asterisk Operator symbol (∗) in HTML, insert the
entity ∗ directly into your markup. The decimal entity ∗ works in any HTML-serialised document.
In CSS pseudo-elements use content: '\2217';.
In JavaScript and TypeScript the escape '\u2217' evaluates to ∗. In Python source, write '\u2217'.
The character encodes to E2 88 97 as UTF-8 bytes and 2217 as UTF-16 code units. Its decimal codepoint is 8727.
This is a text-based Unicode character. It will render in the current font on most platforms. If a font lacks this glyph, the browser may show a placeholder or fall back to a system font.
Things to know
- No compiler will take it. Source code, spreadsheet formulas and command lines want U+002A. Pasting this character produces a syntax error with no visible cause, because most fonts draw the two close enough to read past a dozen times.
- UTS #39 maps it to U+002A in the confusables data. Normalise before any security-sensitive comparison.
- ∗ is its HTML named entity; `∗` and `∗` also work.
- No Windows-1252 slot, so it cannot survive a legacy eight-bit round trip.
- East Asian Width Narrow, so it will not change cell width in a terminal the way multiplication sign can.
- Pattern_Syntax applies; identifier grammars following Unicode's rules reject it.
Comparisons
In the Wild
RFC 9110, the HTTP semantics specification, runs to 454,885 characters of plain text and contains 1,200 ASCII asterisks — and not one occurrence of this character. A document that long, that carefully written and that entirely inside ASCII is the clearest statement available of where the keyboard asterisk's territory ends and this character's never began.
An encyclopaedia article about the multiplication sign uses it once, as a specimen of itself.
FAQ
Can I use it in code?
No. Every language, spreadsheet and shell parses U+002A. This character produces a syntax error that is nearly invisible on screen.
How is it different from the keyboard asterisk?
Vertical position and category. This one is centred on the operand axis and classed Sm; U+002A sits high and is punctuation.
What does Unicode say it means?
Its one annotation says it may be used for the telephony asterisk on keypads. That is the standard's only stated use.
Does it have an HTML entity?
Yes — ∗.
Will a search for `*` find it?
Not unless something folds the two. Unicode's confusables data records them as look-alikes, but that is a security mapping, not automatic behaviour.