Squared (²) & Cubed (³) Symbols

² and ³ (superscript two and three, U+00B2 and U+00B3) are the exponent characters behind x², E=mc², and unit abbreviations like m² and cm³. Unlike the rest of the superscript digits, they've been part of the standard Latin-1 character set since the 1980s — which is why they render correctly in far more places than ⁰, ¹, or ⁴–⁹.

² and ³ are an accident of encoding history as much as a mathematical notation. When ISO 8859-1 (Latin-1) was standardized in 1987 as the dominant 8-bit character set for Western European computing, it included exactly two superscript digits — ² and ³ — because they were already common in French and Scandinavian typewriter fonts for scientific and technical writing, particularly unit abbreviations like m² and cm³. No other superscript digit made the cut.

That left a gap: ⁰, ¹, and ⁴ through ⁹ didn't get standard codepoints until Unicode introduced the dedicated Superscripts and Subscripts block (U+2070–U+209F) years later, largely to support algebraic and chemical notation in full. Because ² and ³ arrived first and rode into every system that adopted Latin-1 — including Windows-1252 — they're the two superscript digits you can count on rendering correctly almost anywhere, while the rest of the set is a more recent, occasionally-unsupported addition.