Double-struck text (also known as Blackboard Bold) uses Unicode characters from the Mathematical Alphanumeric Symbols block (U+1D400–U+1D7FF). These characters appear as bold, outlined letters that are distinct from regular ASCII characters.
The double-struck style originated from mathematicians who used chalkboards, creating bold, outlined letters by double-striking with chalk edges. This distinctive style is commonly used in mathematical notation to represent certain sets like real numbers (ℝ), integers (ℤ), natural numbers (ℕ), and more.
Double-struck text is perfect for creating eye-catching headers, emphasizing important text, or adding a distinctive mathematical appearance to your content. These characters are widely supported across modern platforms and social media.
Double-struck text is different from regular bold formatting. While regular bold is a font style applied to normal characters, double-struck text uses actual Unicode characters that appear bold and outlined by default, making them work consistently across all platforms and giving them a unique mathematical aesthetic.
