Colon Equals HTML entity &colone;

&colone; is the HTML entity for Colon Equals ≔ (U+2254). Copy the decimal ≔ and hex ≔ codes plus CSS, JavaScript, Python and URL escapes.

Entity: &colone;
Also written: &Assign; &coloneq;
Code point: U+2254
Unicode name: COLON EQUALS
Block: Mathematical Operators
Category: Math symbol (Sm)
Since: Unicode 1.1
Defined in: HTML5

Codes to copy

HTML named	`&colone;`Works in HTML; in XML only & < > " ' are predefined.
HTML decimal	`≔`Works in HTML and XML.
HTML hex	`≔`Works in HTML and XML.
CSS	`content: "\2254";`In a stylesheet, for ::before and ::after.
JavaScript	`"\u2254"`Also valid in JSON.
Python	`"\u2254"`Python 3 string literal.
Python by name	`"\N{COLON EQUALS}"`Readable alternative using the Unicode name.
URL	`%E2%89%94`Percent-encoded UTF-8 bytes, for a path or query value.
UTF-8 bytes	`E2 89 94`3 bytes.
UTF-16	`2254`1 code unit, which is what JavaScript length counts.

When to use it

&colone; writes U+2254 (Colon Equals), a maths symbol from the Unicode Mathematical Operators block, encoded since Unicode 1.1. For more than a symbol or two, MathML, supported in all major browsers since 2023, gives proper maths spacing and layout.

The name comes from the HTML5 list (much of it shared with MathML), so it works in every current browser but not in XML or XHTML served as XML, where the numeric reference is the safe choice.

More maths operators

All maths operators · Every HTML entity · Encode or decode text

Source: the WHATWG HTML Standard list of named character references and the Unicode Character Database (Unicode 18.0).