Every method for typing the infinity symbol on Windows, Mac, Linux, iOS, Android and the web, plus the lookalikes to avoid.
The short version
Start here if you only have one minute. The full guide below explains each point.
One code point
U+221E, encoded in 1991 and supported everywhere.
Mac has a direct key
Option and 5, with no setup needed.
Watch the lookalikes
A rotated digit 8 is still a digit.
01
The character itself
The infinity symbol is U+221E, formally named INFINITY. It sits in the Mathematical Operators block and has been encoded since Unicode 1.0 in 1991.
That age is good news. Thirty-five years of font support means it renders essentially everywhere, including in printed and exported documents.
- Code point: U+221E
- Decimal: 8734
- HTML: ∞ or ∞
02
On Windows
Hold Alt and type 8734 on the numeric keypad. The row of numbers above the letters will not work, which is the usual reason this fails.
In Word there is a better route: type 221e and press Alt and X together. The code turns into the character in place.
03
On macOS
Press Option and 5. This is one of the few symbols with a direct shortcut on the standard layout, no configuration required.
The character viewer, opened with Control, Command and Space, is the fallback if the shortcut is remapped.
04
On Linux, phones and the web
On Linux press Ctrl, Shift and U together, release, then type 221e and press Enter or Space.
On iOS and Android the emoji keyboard's symbols section carries it, and a text replacement is faster if you use it often. In HTML, write the named reference and let the browser resolve it.
- Linux: Ctrl+Shift+U, then 221e
- iOS and Android: emoji keyboard, symbols tab
- HTML: ∞
- LaTeX: \infty
05
The lookalikes
Three characters resemble it and are not it. A sideways figure eight from a different block, the lemniscate used in some typefaces, and the ordinary digit 8 rotated by CSS.
Only U+221E is the mathematical infinity. The others will not match in a search and may not convert correctly in an export.
✦If the symbol is doing mathematical work, verify the code point. Visual similarity is not identity.
06
When to type it and when to copy it
Type it if you need it more than occasionally, since the shortcuts are short enough to remember. Copy it for one-off use.
In mathematical writing, prefer a proper equation editor. The character alone cannot express limits, and notation with structure needs a system that understands structure.
Every route to U+221E
One character, eight input methods. Each converts the same code point into the form that platform expects.
| Platform | Method |
|---|---|
| Windows | Alt + 8734 (numeric keypad) |
| Microsoft Word | Type 221e, then Alt + X |
| macOS | Option + 5 |
| Linux | Ctrl + Shift + U, then 221e |
| iOS / Android | Emoji keyboard, symbols section |
| HTML | ∞ or ∞ |
| Excel / Sheets | =UNICHAR(8734) |
| LaTeX | \infty |
Every row produces the identical character. The differences are only in how each platform accepts the number.
07
Copy the symbols discussed in this guide
This guide explains the topic. Use math symbols for the main copyable set, compare it with technical symbols, and browse aesthetic symbols for another useful angle. Each collection includes searchable Unicode names and HTML references.
08
Questions, answered
What is the alt code for the infinity symbol?+
Alt 8734 on Windows, typed on the numeric keypad. The number row above the letters does not work for alt codes.
Why does Alt 8734 do nothing?+
Almost always because the numbers were typed on the top row instead of the numeric keypad, or the laptop has no keypad enabled.
Is the infinity symbol the same as a sideways eight?+
Visually similar, technically not. Only U+221E is the mathematical infinity character; a rotated digit is still the digit.
09
Sources and review notes
Reviewed against Unicode terminology for characters, code points, glyphs, sequences and presentation behavior.