Infinity symbol ∞
Infinity ∞ is a maths text symbol for an infinite number that people had been texting from the times when ASCII encoding was developed. And you can type it right from your keyboard. I'll show you how to do it by using different techniques depending on your Operating System and tastes.
What infinity means
Infinity symbol created by John Wallis in 1655 refers to things without any limit. Usually is used in mathematics or physics to express that some things have no limit. For example, set of natural numbers has no limit and could be expressed by infinity ∞ sign. Infinity is designated as the ∞ symbol because it was imagined as a special variation of ouroborus snake - an ancient symbol depicting a serpent or dragon biting its own tail.
How to input infinity symbol
Choose your system to find out.Windows
Shortcut technique that works on Desktops and most Laptops running MS Windows. You press Alt and, while holding it, type a code on Num Pad while it's turned on. Please, read a guide if you're running a laptop. You can type many frequently used symbols with this method.
Configure your keyboard layout in Windows so that you can type all additional symbols you want as easy as any other text. Takes about 5-10 minutes to set things up, but you'll be typing like a boss. You can assign infinity symbol ∞ and any other text characters to your keyboard using this technique.
CharMap allows you to view and use all characters and symbols available in all fonts (some examples of fonts are "Arial", "Times New Roman", "Webdings") installed on your computer. You can input infinity symbol using it.
Emoji on iOS (iPhone, iPad and iPod touch)
You can make frequently used technical non-fancy symbols like "√ ∑ π ∞ ∆ ™ © æ £ ¢" and åccénted letters on Mac using [Option] key. I've compiled a list of shortcuts in my article and explained how to open keyboard viewer. You can also use your Keyboard Viewer as an alternative to my list.
[Option] +  produces ∞ infinity sign.
Character Palette allows you to view and use all characters and symbols, including infinity, available in all fonts (some examples of fonts are "Arial", "Times New Roman", "Webdings") installed on your computer.
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Character map allows you to view and use all characters and symbols available in all fonts (some examples of fonts are "Arial", "Times New Roman", "Webdings") installed on your computer. It can also help you lookup Unicode codes for entering symbols with keyboard.
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