U+211D "ℝ" Double-Struck Capital R Unicode Character
Unicode Version 17.0
ℝ
U+211D "ℝ" Double-Struck Capital R is a typographic symbol representing the set of real numbers in mathematical notation, originating from blackboard bold typeface conventions used to denote number systems. It is part of the Letterlike Symbols block and is commonly employed in algebra, calculus, and analysis to signify the continuum of all rational and irrational numbers. This character allows for clear, unambiguous communication in mathematical texts, academic papers, and digital formats without relying on formatting tricks like bolding.
General Properties
| Code Point | U+211D |
| Version Added | 1.1 |
| Name | Double-Struck Capital R |
| Unicode 1.0 Name | Double-Struck R |
| Block | Letterlike Symbols |
| General Category | Uppercase Letter |
| Canonical Combining Class | Not Reordered |
| Bidirectional Class | Left To Right |
| Decomposition Type | Font |
| Decomposition Mapping | "R" U+0052 Latin Capital Letter R |
Encodings
| HTML Decimal Encoding | ℝ |
| HTML Hex Encoding | ℝ |
| UTF-8 Encoding | 0xE2 0x84 0x9D |
| UTF-16 Encoding | 0x211D |
| UTF-32 Encoding | 0x0000211D |
| C/C++/Java Escape | \u211d |
Unicode Properties
| NFC Quick Check | Yes |
| NFD Quick Check | Yes |
| Numeric Type | None |
| Numeric Value | NaN |
| Line Break | Alphabetic |
| Uppercase | Yes |
| Cased | Yes |
| Changes When NFKC Casefolded | Yes |
| NFKC Casefold | "r" U+0072 Latin Small Letter R |
| NFKC Simple Casefold | "r" U+0072 Latin Small Letter R |
| Script | Common |
| Script Extensions | Common |
| Indic Syllabic Category | Other |
| ID Start | Yes |
| XID Start | Yes |
| ID Continue | Yes |
| XID Continue | Yes |
| Alphabetic | Yes |
| Math | Yes |
| Other Math | Yes |
| Vertical Orientation | Rotated |
| Grapheme Base | Yes |
| Grapheme Cluster Break | Other |
| Word Break | Alphabetic letter |
| Sentence Break | Upper |