How to type the infinity symbol on Windows

Why there is no zero in this code

∞ is not in Windows-1252, so the four-digit Alt + 0xxx form cannot reach it. It is in code page 437, the original IBM PC character set, at position 236. Typing Alt + 0236 therefore gives a completely different character (ì), while Alt + 236 gives infinity. The same table is where Alt + 227 for π and Alt + 251 for √ come from.

Infinity in Word equations

For maths, Word’s equation editor is the tidiest option. Press Alt + = to start an equation, type \infty and press space: it becomes ∞ in proper maths spacing. The same editor understands \pm for ± and \pi for π, which is useful if you are writing limits such as lim x→∞. For ordinary text, the alt code is quicker.

On a laptop

Without a numeric keypad, use one of these: the embedded keypad (Fn + NumLk), the emoji panel’s Symbols tab (Win + ., then look under maths symbols), 221E + Alt + X in Word, or a copy from the infinity symbol page. The Character Map guide shows how to search for it by name.

∞, ♾️ and 8

The emoji ♾️ (called “infinity” on phones) is a separate character, U+267E, and shows in colour or as a heavier glyph. Use ∞ in maths and science, and keep ♾️ for chats. Browse the rest of the math symbols if you need related signs such as ≈ or ∝.