One half symbol ½

• Recipes: ½ cup sugar, 1½ tsp vanilla.
• Measurements: a ½-inch bolt, 5½ feet, US letter paper at 8½ × 11 in.
• Sizes and standings: shoe size 9½, a 2½-game lead.

Write mixed numbers with no space: 2½, not 2 ½. Word’s AutoFormat turns typed 1/2, 1/4 and 3/4 into ½, ¼ and ¾; other fractions stay as typed.

Precomposed fractions exist only for a limited set. ¼ ½ ¾ come from the old Latin-1 set, and ⅓ ⅔ ⅕ ⅙ ⅛ and a few others are in Unicode’s Number Forms block. For any other fraction, such as 5/16, use digits with a slash, or the fraction slash ⁄ (5⁄16) with a font that supports fraction formatting.

The single character is great for display but can cause trouble elsewhere:

• Search and data: ½ and 1/2 are different text. A search for “1/2 cup” may not find “½ cup,” and spreadsheets treat ½ as text, not 0.5. In data, store 0.5.
• Mixed styles: if a recipe needs ¼, ½ and 5/8, the precomposed fractions and the typed one look inconsistent. Use one style throughout.
• Accessibility: screen readers don’t all announce ½ the same way. In instructions where precision matters, “1/2” or “one-half” is the safe choice.
• Font support: ½ is in nearly every font, but rare fractions such as ⅐ (one seventh) may show up as boxes.

The fraction slash ⁄ looks like a regular slash but is designed to sit between raised and lowered digits.

• Mac: open the Character Viewer with Control+Command+Space and search “one half,” or add a text replacement (1/2 → ½) in System Settings > Keyboard > Text Replacements.
• Word: type 1/2 followed by a space, and AutoFormat converts it.
• Excel: typing 1/2 into a cell turns it into a date (January 2). Type 0 1/2 instead, or enter 0.5 and apply the Fraction number format, which displays 1/2 while keeping a real number.
• Phones: set up the same text replacement, or copy it here.
• LaTeX: \frac{1}{2} in math mode, or \nicefrac{1}{2} with the nicefrac package for an inline fraction.