Mathematical Bold Script Capital I 𝓘

Visual Description: A tall, elegant capital I in a bold script style. The strokes curve smoothly, with a slight italic tilt and airy flourishes at the ends. The glyph reads like a handwritten letter set in a mathematical font, distinct from plain, straight letters. It looks decorative yet legible.

Meaning & Usage: It serves as a stylized variable or object marker in formulas, denoting a distinguished quantity. In math editors and calculators, it helps differentiate a particular element from ordinary letters. You may apply bold script for emphasis or to signal objects that participate in comparisons.

Historical Background: The bold script style grew from calligraphic traditions and digital fonts that expand the range of math symbols. It was introduced in the mathematical alphanumeric family to distinguish variables and named objects from plain letters. In classrooms and software, designers gradually adopted this glyph to add clarity without words.

Practical Use: In formulas, use the glyph to highlight an element, a matrix entry, or a named constant. In calculators and equation editors, you can insert it from a symbol menu or via a font/style toggle. Use quick UI controls to switch to bold script for operations or comparisons, such as I + J or I = J, without extra text.

See our category page for related symbols.

Look‑alikes: l (U+6C).

Need styled alternatives? Try the Fancy Text tool.