HTML Entity for Double Struck Italic Capital D (ⅅ)
Beginner
5 min read
Updated: Sep 2026
1 example
Unicode U+2145
Definition
What Is Double Struck Italic Capital D?
Double-struck italic capital D (ⅅ) is the Unicode character at U+2145 in the Letterlike Symbols block. Official name: DOUBLE-STRUCK ITALIC CAPITAL D. It is used in mathematics as a capital differential operator.
Remember
Character ⅅ
Unicode U+2145
Named entity ⅅ
Hex entity ⅅ
Decimal ⅅ
CSS escape \2145
Not the same ⅆ (ⅆ) · D · ∂
Prefer ⅅ in HTML markup (also aliased as ⅅ). You can also type ⅅ in UTF-8, or use numeric forms when needed.
Double-struck italic capital D rendered alone and in a simple math use.
Exampleⅅf
Large glyphⅅ
Comparedⅅ ⅆ D ∂
With entitiesNamed: ⅅ | Hex: ⅅ | Decimal: ⅅ
Code
Complete HTML Example
One page that shows Double Struck Italic Capital D with named, hex, decimal, CSS escape, and a typed character. Use View Output or open the live editor.
Named + Hex + Decimal + CSS + Typed
Five ways to produce ⅅ, plus a comparison with the small form ⅆ.
html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Double Struck Italic Capital D (ⅅ) in HTML</title>
<style>
#point::after {
content: "\2145";
}
</style>
</head>
<body>
<p>Capital D using Named Entity: ⅅ</p>
<p>Capital D using Hex Code: ⅅ</p>
<p>Capital D using HTML Code: ⅅ</p>
<p id="point">Capital D using CSS Entity: </p>
<p>Typed directly: ⅅ</p>
<p>Differential: ⅅf vs ⅆx</p>
</body>
</html>
Capital D using Named Entity: ⅅ
Capital D using Hex Code: ⅅ
Capital D using HTML Code: ⅅ
Capital D using CSS Entity: ⅅ
Typed directly: ⅅ
Differential: ⅅf vs ⅆx
How It Works
1. Named:ⅅ is the HTML5 name for U+2145 → ⅅ. Best default in markup (also ⅅ).
2. Hex:U+2145 → ⅅ in HTML. Same glyph as the named form.
3. Decimal: same code point as 8517 → ⅅ. Same result as hex and named.
4. CSS: use \2145 in content (not an HTML entity). #point::after appends that ⅅ after the paragraph text.
5. Typed / uses: paste ⅅ in UTF-8, or write ⅅf vs ⅆx to contrast capital and small differentials.
Pitfalls & Tips
Common mistakes when working with Double Struck Italic Capital D.
Case
Capital DD matters
ⅅ is capital ⅅ (U+2145). ⅆ is small ⅆ (U+2146). The names are case-sensitive.
D
Not a styled letter D
Italic or bold CSS on ordinary D (U+0044) is not the same code point as ⅅ. Use the Letterlike Symbol when you need the differential glyph.
ⅆ
Pair with small dd
For expressions like ⅅf / ⅆx, use ⅅ for the capital operator and ⅆ for the small differential.
Alias
Longer name works too
ⅅ is an HTML5 alias for the same character as ⅅ. Prefer the short form in everyday markup.
CSS vs HTML
Do not mix escapes
\2145 belongs in CSS strings. ⅅ / ⅅ / ⅅ belong in HTML.
Fonts
Math font coverage
Some fonts omit Letterlike Symbols. Prefer a math-capable font for reliable display of ⅅ.
Semicolon
End named entities
Always finish with ; — write ⅅ, not &DD.
Compatibility
Browser Support
Double-struck italic capital D (U+2145) and its entity forms (ⅅ, ⅅ, ⅅ, CSS \\2145) are supported in all mainstream browsers. Visible glyphs depend on math / Letterlike Symbols font coverage.
✓ Universal support
Double Struck Italic Capital D (ⅅ)
Encode with named, hex, decimal, CSS escape, or type the character — same code point everywhere encoding is supported.
100%Browser coverage
Google ChromeSupported
Yes
Microsoft EdgeSupported
Yes
Mozilla FirefoxSupported
Yes
Apple SafariSupported
Yes
OperaSupported
Yes
Internet ExplorerAll versions
Yes
U+2145 / entitiesFull support
Bottom line: Prefer ⅅ in HTML. Use ⅅ / ⅅ when numeric form is required, and \\2145 only inside CSS content.
Remember
Key Takeaways
Unicode: double-struck italic capital D is U+2145 (decimal 8517) — glyph ⅅ.
HTML: prefer ⅅ — also ⅅ / ⅅ / type ⅅ.
CSS: use \2145 inside content for generated text.
Meaning:ⅅ = capital differential D — not ⅆ, not a styled letter D.
Use ⅅ (named), ⅅ (hex), ⅅ (decimal), type ⅅ directly in UTF-8, or the CSS escape \2145 in content. Prefer ⅅ in normal HTML.
U+2145 (DOUBLE-STRUCK ITALIC CAPITAL D). Hex 2145, decimal 8517. It belongs to the Letterlike Symbols block (U+2100–U+214F).
Yes. Use ⅅ (or the longer alias ⅅ). Numeric forms ⅅ and ⅅ also work. Do not use ⅆ — that is the small form U+2146.
Use it in mathematical or scientific text for the capital differential / double-struck italic D. Prefer ⅆ for the small differential d (U+2146).
HTML entities (ⅅ, ⅅ, or ⅅ) go in markup. The CSS escape \2145 goes in stylesheet strings (usually content on ::before/::after).
No. ⅅ is ⅅ (U+2145). ⅆ is ⅆ (U+2146). A styled CSS italic D is still the ordinary letter U+0044 — not this Letterlike Symbol.
🤔
Did you know?
Double-struck italic capital D is Unicode U+2145 (decimal 8517) — glyph ⅅ in the Letterlike Symbols block. HTML5 names it ⅅ (also ⅅ). Common use: capital differential operator in math (e.g. ⅅf). The small form is ⅆ (U+2146).
