How to Type the Infinity Symbol: Every Shortcut You Actually Need

You're staring at your keyboard, looking for that sideways eight. It isn't there. Honestly, it’s kinda weird that one of the most famous mathematical concepts doesn’t have its own dedicated key, but here we are. Whether you're a student finishing a calculus paper, a designer working on a logo, or just someone trying to look deep on social media, knowing how to type the infinity symbol is one of those tiny digital hurdles that everyone hits eventually.

It's frustrating. You’ve probably already tried holding down Shift and every number across the top row. No luck. Most people just end up Googling the symbol and copy-pasting it, which works once, but it’s a massive pain if you have to do it twenty times in a document.

The Quickest Ways for Windows Users

Windows is notorious for having hidden shortcuts that feel like secret handshakes. If you have a full-sized keyboard with a numeric keypad on the right side, you're in luck. This is the "old school" way. Hold down the Alt key and type 236 on that number pad. The moment you let go of Alt, the ∞ symbol appears. It feels like a magic trick.

But wait.

Most laptops these days don't have that dedicated number pad. If you're on a Surface or a Dell XPS, the Alt-code method usually won't work unless you mess with a Function (Fn) key, and even then, it's hit or miss. Instead, try the Emoji Panel. Press the Windows Key + . (period) or Windows Key + ; (semicolon). A little window pops up. Most people use this for fire emojis or laughing faces, but if you click on the symbols icon (the little omega Ω), you can scroll down and find the infinity sign. It’s usually tucked away in the "Math Symbols" subsection.

Microsoft Word has its own logic, too.

Inside Word, you can type 221e and then immediately press Alt + X. The text magically transforms into the infinity symbol. It’s a specific Unicode trick that works across most Microsoft Office products. If you’re a power user, this is significantly faster than hunting through the "Insert Symbol" menu, which feels like it was designed in 1995 and hasn't changed since.

Mac Shortcuts: Simplicity Wins

Apple usually makes this stuff a lot easier. On a Mac, you don't need to memorize a string of random numbers. You just hit Option + 5. That’s it.

I’ve always found it interesting that Apple chose the 5 key for this. Maybe because it’s in the middle? Who knows. If you’re using an iPad with a physical keyboard, this same shortcut usually carries over. However, if you're using the on-screen keyboard on an iPhone or iPad, there is no "infinity" key hidden under the numbers. You either have to copy-paste it from a website or set up a Text Replacement.

Go to Settings, then General, then Keyboard, and finally Text Replacement. Hit the plus sign. For the "Phrase," paste the ∞ symbol. For the "Shortcut," type something like "inf" or "infin." Now, every time you type that word, your phone will suggest the symbol. It’s a lifesaver for people who deal with math or philosophy notes on the go.

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The Web and Coding Reality

Writing for the web is a different beast entirely. If you’re a developer or you’re editing a website’s HTML, you can't always rely on your keyboard shortcut to render correctly for everyone else. Browsers can be picky about character encoding.

To be safe, use the HTML entity. You have two main options:

• ∞ (This is the "named" entity and it's easy to remember)
• ∞ (The decimal version)

If you’re working in CSS and want to add the symbol as content before or after an element, you’d use the Unicode escape: \221E.

Why the Symbol Looks Different Sometimes

You might notice that the infinity symbol looks "fat" in some fonts and "skinny" in others. This isn't a glitch. The symbol, technically known as the lemniscate, follows the design rules of the typeface you're using. In a serif font like Times New Roman, it has varied stroke weights. In a sans-serif like Arial, it’s a uniform loop.

John Wallis is credited with introducing this symbol into mathematics back in 1655. He never explicitly explained why he chose it, but historians think it might be a variation on the Roman numeral for 1,000 (CIƆ), which was sometimes used to represent "many."

Troubleshooting the "Question Mark Box"

Sometimes you type the symbol, and it looks perfect on your screen. You send the email, and the person on the other end sees a weird box with a question mark inside it (). This is a character encoding issue.

Basically, the "language" of your document (like UTF-8 versus ASCII) doesn't recognize the infinity symbol. If you're seeing this, ensure your document or email settings are set to Unicode (UTF-8). This is the modern standard that includes almost every symbol ever created, from ancient hieroglyphs to that sideways eight you’re trying to use.

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Actionable Summary for Fast Access

Depending on your device, here is exactly what you should do right now:

• Mac: Press Option + 5.
• Windows (with NumPad): Hold Alt and type 236.
• Windows (Laptop): Press Win + . and search the symbol menu.
• Microsoft Word: Type 221e and then hit Alt + X.
• Google Docs: Go to Insert > Special Characters and search for "infinity."
• iPhone/Android: Copy the symbol ∞ and create a Text Replacement shortcut in your settings.

Instead of searching for this every time, pick the method that fits your workflow and try it three times in a row. Muscle memory is a much better tool than a Google search. If you’re doing heavy mathematical writing, consider switching to an environment like LaTeX where the command is simply \infty. It’s consistent, professional, and avoids all the formatting headaches of standard word processors.